Florida.

Ocala National Forest
Trails only. Mixed use. Dirtbike, quads, sxs, jeeps.
About 3 hours north of Tampa.
http://www.fs.usda.gov/wps/portal/fsinternet/!ut/p/c4/04_SB8K8xLLM9MSSzPy8xBz9CP0os3gjAwhwtDDw9_AI8zPwhQoY6BdkOyoCAPkATlA!/?ss=110816&navtype=BROWSEBYSUBJECT&cid=FSE_003853&navid=091000000000000&pnavid=null&position=BROWSEBYSUBJECT&ttype=main&pname=Ocala%20National%20Forest-%20Home

Eastbay MX
MX only. Dirtbike and quad.
20 minutes south of Tampa
http://www.eastbaymotorsports.com/

Dade City MX
MX only. Dirtbike and quad freindly.
45 minutes north of Tampa.
http://dadecitymx.com/

Bartow MX
MX only. Dirtbike and quad.
1 hour east of Tampa
http://www.bartowmotocross.com/

Florida Tracks and Trails.
NOT OPEN YET. Proposed opening 1-?-2014
26+ miles of ONE WAY trails, dirtbike, sxs, quad.
4, possibly 5 progressively challenging MX tracks. EXTREMELY quad friendly. (I know the manager, he is a quad guy)
2 hours south of Tampa.
https://touch.facebook.com/home.php?refid=8&_rdr#!/home.php?soft=side-area&__user=100000262782833