Yes the Thimbles really are beautiful and a great place to spend a day sailing or paddling.  My great grandfather used to own one of them (Davis Island on the chart) and i remember visiting it as a kid.  I took my dory down there a couple of years ago and had a wonderful day.   

You can launch from the village public boat ramp right in the village of Stony Creek.   Parking is very limited but a church right across the street from the village landing/park has figured out a new revenue stream and offers super-convenient trailer parking on Saturdays.  So go Saturday if you can.  I assume it is not available on Sunday. 

There is only one island that you can land on, the rest are private.  Bring an anchor if you want to stop for lunch.  

   The sail east to Sachem Head is also worthwhile to figure into your day!

   Another amazing CT site is the Barn Island Boat Ramp in Stonington. You can paddle/row/sail little narreganset bay to Stonington Harbor, Napatree beach, Watch Hill   Harbor, and other sites in Fishers Island Sound.

CT DEEP has all the state boat launches on their website.

Joel