RE: St George Island SP, FL
St George has a few pull thru's at the back of the park. But don't worry its not that large a camp ground. There are many good sites and our favorites are the ones on the South side, closest to the Gulf if you look on a map. I have pics if you care to peruse my blog.
Bugs, yup and plenty of 'em. They do spray but it only holds back the hordes. Take a screened in portch and a high velocity fan (as somebody else mentioned) and plenty of bug spray.
Its a beautiful park. One of our faves. Enjoy.
RE: Topsail Hill SP or Fort Pickens CG?
I agree with MT Pokets, apples and oranges between these two parks.
First: if you are looking for full hook up then TopSail is your park. IF you are looking for more rustic (though I use this in a loose term) then Ft Pickens is for you. They are VERY different camping experiences. If you choose Pickens, choose the A loop as it still has some trees. The big loop B lost all its trees when hurricane Dennis and Ivan washed over the CG.
History is amazing at Pickens as are the pristine beachs. Expect to ride a bike part of the way and walk the boardwalk the rest for Pickens. Topsail, you can either catch the free trolly or ride your bike about a mile between the CG and the beach.
I have gone to Ft Pickens since I was a kid in the 60's and love it. I've also been to Topsail for the past 10 years with my kids and love it for totally different reasons.
Pickens has water and electric, coastal batteries and 1800's brick fort. Top sail is full hook up with a pool, shuffle board and very close to Destin and fab. hwy 30A. Its all what you are looking for.
Last thought...going to either of these parks in Febuary is potentialy going to be chilly. Its not the Florida where snow birds go...they go further south.
Its all what you want to experience.