IMO... I think they cost too much. You can bring friends but it's gonna cost more thru the Jamboree then planning your own trip to the Badlands.
You could easily find a 4x4 club or group in your area and go with them or even check posts on this forum or Jeepforum.com since there are always people going to the Badlands. I usually go there twice a year since it's a 6hr drive and have to tow my "Beast"
4x4 groups and clubs are more then willing to show ya around and help ya out as well, its one of the best way to get to know your Jeep and meet other wheeling friend.
Look under the Great Lake Wheeling thread....
Great Lakes USA - JeepForum.com