There used to be, but I've been gone from there for years now. Every time I've gone back, more stuff is developed.
Lehigh/Alva/North Cape might help narrow the search. FTMyersTRD is around here somewhere, you might want to get ahold of him (I've seen him put up some pictures from rides and such before). A huge place near you is: Big Cypress National Park ORV Bear Island, which you might want to check out too.
I live in Lehigh and usually hit some ATV trails that are out here, nothing special just mud. I know TJ Cruiser has been to a few spots. One in N. Ft. Myers and one in Bonita. I think the one in Bonita is off of Bonita Beach Rd at the end going east. The one in N. Ft. Myers is somewhere off of Cook-Brown Rd around SR 31 and Bayshore area. I never been to either spots, but see pics and heard other people talk about them.
East Bonita has some trails, watch out for the ATV's and the paint ball warriors. Follow EAST TERRY st, east and your there. The road turns into dirt and goes back a mile or two or more. Look for the sign that says something about "video surveillance", turn right there and go back and find more trails. Just obey the posted No Trespassing signs nailed to the trees and you will not have any problems. Great for ATV's, good for FJ's. Lots of tight trails for the ATV market. I've got plenty of brush scratches from playing there in the FJ.