Durhamtown P has no comparison to any of the parks GATR rocks.
I'm a fan of DP for a romp on some muddy trails and some hill climbs with my non-rock crawling friends (i.e., work associates), but it is not a park for everyone.
Of the parks I've been to with GATR, Choccolocco and Gulches have the best maps, but Chocco, and most other parks, leaves a lot to be desired regarding trail markings and maps. It is frustrating to try to use the maps for most of these parks.
The people who operate DP, especially the staff at the cabin/check-in place, are not real friendly and treat people like idiots if they don't know how their park operates. The good news is that you should only have to deal with them for a few minutes every trip, and then you can do pretty much anything you want to do since it is at the edge of being an anarchist operation. I have never been wrist band checked, I've popped out on someones land, people drink beer openly while riding (not me, of course), and sometimes you randomly end up on the side of some road instead of the trail.
The cost of the various parks is a strange thing to me. There is not standard between all of the parks. I do not know why having one person, two people, or 10 people in a vehicle affects the cost of using the trails (I do have one theory). I don't understand why they charged you based on the number of drivers versus the number of vehicles. DP NOTE: on my first trip to DP I was with a bunch of work associates. We got to the first trail we came across and just started riding, without checking in. Then at the end of the day the host of the event went to the office to pay and they told him not to worry about it and come back again sometime. A free day of riding for us, except for the guy who blew his radiator and had to do a field repair at a 45* angle.
I wish you better luck in the future.