This script imports Simplenote notes into Evernote while preserving file creation and modification dates and using the first line of the text as the note title. Download your Simplenote notes as .zip, extract them, run the script, and select the folder with your extracted notes.

simplenote-to-evernote.applescript

set listOfNames to {}
set simplenoteFolder to choose folder "Select the folder with your extracted Simplenote txt files"
tell application "Finder"
	set filelist to (every file of the folder simplenoteFolder) as alias list
	repeat with currentFile in filelist
		set firstLine to (first paragraph of (read currentFile as «class utf8»))
		set creationDate to (the creation date of currentFile)
		set modificationDate to (the modification date of currentFile)
		set folderName to (the name of simplenoteFolder)
		tell application "Evernote"
			set theItem to create note title firstLine created creationDate notebook folderName from file currentFile
			set (modification date of theItem) to modificationDate
		end tell
	end repeat
end tell