Definitely purchase Bill Keogh's book The Florida Keys Paddling Guide. It is
well worth the money. Available on Amazon.
Bill's guide service is also a good bet if you would like a guide.
Look for directions to The Old Wooden Bridge Guest Cottages and Marina on Big Pine Key. This is where he operates out of.
http://www.oldwoodenbridge.com/
Here's the link to his site ...
http://www.keyskayaktours.com/
The book has every conceivable "put in" listed by mile marker from Southern most point to Card Sound.
Along with some historical and ecological info near each "put in".
I have a ton more info on launches/wading/eats/etc. but too much to post.
Send me a PM or e-mail me if you'd like some more info.
"Only the half-mad are wholly alive." ~~ Edward Abbey