InDesign project folder restructure and rename

PrepScriptv05

set text item delimiters to "."
tell application "Finder"
	
	--SETUP
	--get Job code
	display dialog "Enter Job Code:" default answer "JobCode"
	set projCode to text returned of result
	--designate project folder
	set projectFolder to choose folder with prompt "Select project folder"
	
	--ZIP FONTS & RENAME
	tell application "Finder"
		set zipSuffix to "_TYPEFACES"
		--pick font folder
		set inputFolder to choose folder with prompt "Select font folder to be zipped"
		tell current application
			set qpp to quoted form of POSIX path of inputFolder
			do shell script "cd $(dirname " & qpp & ")
    zip -r  \"$(basename " & projCode & zipSuffix & ").zip\" \"$(basename " & qpp & ")\""
		end tell
		--delete original files
		delete inputFolder
	end tell
	
	--CREATE NEW PROJECT FOLDERS AND SORT FILES
	make new folder at projectFolder with properties {name:"HIRES"}
	--set path to move to HIRES folder
	set hiFiles to (projectFolder as string) & "HIRES"
	
	-- move all files to HIRES
	set targetFiles to get every item of (entire contents of projectFolder) whose kind ≠ "Folder"
	--more files into HIRES
	move targetFiles to hiFiles
	--remove extraneous folders
	delete (every folder of projectFolder whose name is not "HIRES")
	--create previews folder
	make new folder at projectFolder with properties {name:"PREVIEWS"}
	
	--DESIGNATE MAIN MECHANICAL
	tell application "Finder"
		--pick the file
		set mainMech to (choose file with prompt "Select primary mechanical file:")
		--get the filename to save the extension
		set mainFNCount to text items of (get name of mainMech)
		--pull original filename extension
		if number of mainFNCount is 1 then
			set mainExt to ""
		else
			set mainExt to "." & item -1 of mainFNCount
		end if
		--rename file
		set the name of mainMech to projCode & mainExt as string
	end tell
	
	--DESIGNATE MAIN PDF
	tell application "Finder"
		--pick the file
		set mainPDF to (choose file with prompt "Select primary PDF file:")
		--get the filename to save the extension
		set mainFNCount to text items of (get name of mainPDF)
		--pull original filename extension
		if number of mainFNCount is 1 then
			set mainExt to ""
		else
			set mainExt to "." & item -1 of mainFNCount
		end if
		--rename file
		set the name of mainPDF to projCode & "_PDF01" & mainExt as string
	end tell
	
	--RENAME ALL _ART FILES IN SEQUENCE
	tell application "Finder"
		set all_files to every item of (choose file with prompt "Select all _ART files:" with multiple selections allowed) as list
		
		--add in the support filename suffix
		set artSuffix to "_ART"
		
		--start looping through all selected files. 'index' is our counter that we initially set to 1 and then count up with every file.
		--the 'index' number is required for the sequential renaming of files
		repeat with index from 1 to the count of all_files
			--using our index, we select the appropriate file from our list
			set this_file to item index of all_files
			set file_name_count to text items of (get name of this_file)
			
			--if the index number is lower than 10, we will add a preceding "0" for a proper filename sorting later
			if index is less than 10 then
				set index_prefix to "0"
			else
				set index_prefix to ""
			end if
			
			--lets check if the current file from our list (based on index-number) has even any file-extension
			if number of file_name_count is 1 then
				
				--file_name-count = 1 means, we extracted only 1 text-string from the full file name. So there is no file-extension present.
				set file_extension to ""
			else
				--re-add the original file-extension after changing the name of the file
				set file_extension to "." & item -1 of file_name_count
			end if
			
			--rename file, add the sequential number from 'index' and add the file-extension to it
			set the name of this_file to projCode & artSuffix & index_prefix & index & file_extension as string
		end repeat
		display notification "File Rename Complete " & index & " files with '" & projCode & "' for you."
	end tell
	
	--RENAME ALL _BIT FILES IN SEQUENCE
	tell application "Finder"
		set all_files to every item of (choose file with prompt "Select all _BIT files:" with multiple selections allowed) as list
		
		--add in the support filename suffix
		set bitSuffix to "_BIT"
		
		--start looping through all selected files. 'index' is our counter that we initially set to 1 and then count up with every file.
		--the 'index' number is required for the sequential renaming of files
		repeat with index from 1 to the count of all_files
			--using our index, we select the appropriate file from our list
			set this_file to item index of all_files
			set file_name_count to text items of (get name of this_file)
			
			--if the index number is lower than 10, we will add a preceding "0" for a proper filename sorting later
			if index is less than 10 then
				set index_prefix to "0"
			else
				set index_prefix to ""
			end if
			
			--lets check if the current file from our list (based on index-number) has even any file-extension
			if number of file_name_count is 1 then
				
				--file_name-count = 1 means, we extracted only 1 text-string from the full file name. So there is no file-extension present.
				set file_extension to ""
			else
				--re-add the original file-extension after changing the name of the file
				set file_extension to "." & item -1 of file_name_count
			end if
			
			--rename file, add the sequential number from 'index' and add the file-extension to it
			set the name of this_file to projCode & bitSuffix & index_prefix & index & file_extension as string
		end repeat
		display notification "File Rename Complete " & index & " files with '" & projCode & "' for you."
	end tell
	
	--RENAME ALL _LYRD FILES IN SEQUENCE
	tell application "Finder"
		set all_files to every item of (choose file with prompt "Select all _LYRD files:" with multiple selections allowed) as list
		
		--add in the support filename suffix
		set lyrdSuffix to "_LYRD"
		
		--start looping through all selected files. 'index' is our counter that we initially set to 1 and then count up with every file.
		--the 'index' number is required for the sequential renaming of files
		repeat with index from 1 to the count of all_files
			--using our index, we select the appropriate file from our list
			set this_file to item index of all_files
			set file_name_count to text items of (get name of this_file)
			
			--if the index number is lower than 10, we will add a preceding "0" for a proper filename sorting later
			if index is less than 10 then
				set index_prefix to "0"
			else
				set index_prefix to ""
			end if
			
			--lets check if the current file from our list (based on index-number) has even any file-extension
			if number of file_name_count is 1 then
				
				--file_name-count = 1 means, we extracted only 1 text-string from the full file name. So there is no file-extension present.
				set file_extension to ""
			else
				--re-add the original file-extension after changing the name of the file
				set file_extension to "." & item -1 of file_name_count
			end if
			
			--rename file, add the sequential number from 'index' and add the file-extension to it
			set the name of this_file to projCode & lyrdSuffix & index_prefix & index & file_extension as string
		end repeat
		display notification "File Rename Complete " & index & " files with '" & projCode & "' for you."
	end tell
	
	--RENAME ALL _IL FILES IN SEQUENCE
	tell application "Finder"
		set all_files to every item of (choose file with prompt "Select all _IL files:" with multiple selections allowed) as list
		
		--add in the support filename suffix
		set ilSuffix to "_IL"
		
		--start looping through all selected files. 'index' is our counter that we initially set to 1 and then count up with every file.
		--the 'index' number is required for the sequential renaming of files
		repeat with index from 1 to the count of all_files
			--using our index, we select the appropriate file from our list
			set this_file to item index of all_files
			set file_name_count to text items of (get name of this_file)
			
			--if the index number is lower than 10, we will add a preceding "0" for a proper filename sorting later
			if index is less than 10 then
				set index_prefix to "0"
			else
				set index_prefix to ""
			end if
			
			--lets check if the current file from our list (based on index-number) has even any file-extension
			if number of file_name_count is 1 then
				
				--file_name-count = 1 means, we extracted only 1 text-string from the full file name. So there is no file-extension present.
				set file_extension to ""
			else
				--re-add the original file-extension after changing the name of the file
				set file_extension to "." & item -1 of file_name_count
			end if
			
			--rename file, add the sequential number from 'index' and add the file-extension to it
			set the name of this_file to projCode & ilSuffix & index_prefix & index & file_extension as string
		end repeat
		display notification "File Rename Complete " & index & " files with '" & projCode & "' for you."
	end tell
	
end tell

Tripped over myself on this one. Is there a way I can have it "skip" a step if a certain file type in the script ("_ART," "BIT", etc) is not in the project? Cancelling out midway through terminates the script entirely and I'd like to give the user a choice. I'm also wondering if between each prompt to pick a folder, if it can automatically start at the projectFolder level? I know this script is verbose, but this is my first attempt at working in AppleScript. Thanks!