I've had that same problem with gates going up after a few trips to a place. I've tried asking permission, but usually can't find out who owns the land.
I'd be willing to meet up at Durhamtown. I couldn't get the link to their rules to work. I'm actually moving down to Dublin in two weeks, so I won't be around Atlanta very much any more, but that will actually be closer to me than it currently is. My fiance's brother has an AEV Jeep Unlimited and I've been trying to get our schedules together to go to a nearby trail ride someday. He hasn't been out in a while, so I'm sure he's itching to break something.
Even though I'm from the Dallas area, I've never been to the Dallas mud bog. I've heard there are trails there, but I'm not sure. I'm still looking into that. I don't like messing with mud like they have there, but its pretty much impassable in anything other than 47" or tractor tires anyway. I linked their website. If I find out there are actual trails and not just mud holes, I may go check that out.