A short script to check for a network connection and attempt to reconnect if not.

Reconnect.scpt

-- Lines 1-29 from: http://apple.stackexchange.com/a/35399
set connected to false

-- Ping the primary OpenDNS server.
try
	set pingResult1 to do shell script "ping -c 1 208.67.222.222"
on error
	set pingResult1 to ""
end try

-- Check the results returned and return true or false.
set p to number of paragraphs in pingResult1
if p < 5 then
	-- Ping another Open DNS server for redundancy.
	try
		set pingResult2 to do shell script "ping -c 1 208.67.220.2220"
	on error
		set pingResult2 to ""
	end try
	
	set p to number of paragraphs in pingResult2
	if p < 5 then
		set connected to false
	else
		set connected to true
	end if
else
	set connected to true
end if

set logFile to (path to desktop as text) & "reconnectLog.txt"

if not connected then
	appendToDisk from ((current date) as text) & " Disconnected
" into logFile
	
-- Lines 38-40 from: http://apple.stackexchange.com/q/32926
	do shell script "networksetup -setairportpower AirPort off"
	delay 3
	do shell script "networksetup -setairportpower AirPort on"
else
	appendToDisk from ((current date) as text) & " Connected
" into logFile
end if

-- Lines 47-57 from: http://stackoverflow.com/a/34272894
on appendToDisk from theText into thePath
	try
		set fileDescriptor to open for access file thePath with write permission
		write theText to fileDescriptor starting at eof
		close access fileDescriptor
	on error
		try
			close access file thePath
		end try
	end try
end appendToDisk

Explanation can be found on my website.