I grew up in Anniston and have ridden many trails there. Unfortunately, most of them are illegal to ride. There are mulititudes of trails in the national forest, but if you get caught they will either write you a ticket or impound your vehicle.
There is one in Jax that everyone calls "dump road". You have to go through a neighborhood to get there and I've heard that the cops stake it out now. They don't want people going up there anymore because some rednecks have been dumping trash.
Some guys have started riding on the old Ft. McClellan property, but I have heard that they are cracking down on that too. Something about the dangers of unexploded ordinance.
There are some trails in the Piedmont area (Oakee Mountain) that are hidden away nicely. They are near Borden Springs. You would have to have a guide to show you there because it is way back in the woods and you could easily get lost. The trails are easy to mild, but it's very scenic. The only thing about that trail is that I normally go armed because Piedmont is known to have some good old boys growing illegal crops way back in the mountains. I have never had any problems on those particular trails though. There is also a watershed lake back there for some summer time swimming.