Does anyone from TN know any offroading areas?

Try Coal Creek ORV area, just west of Oak Ridge.

Coal Creek Area

Just went to the site and they no longer post a map of the area like they used to. I have it in PDF form if you're interested. They do have 4X4 truck friendly trails along with ATV-only trails.

Also, some of the folks in east TN and Georgia apparently know of a place around Helen, GA, not to far south and east of Chattanooga.

Coal Creek is the best wheeling around short of Tellico, definitely worth the 3 hour drive.
Looks like mostly redneck-style wheeling, but www.wheelininthecountry.com might be worth looking into.
Land Between the Lakes has some trails, pretty flat and wet though.

Brent