My 2 cents: Put the bikes in the bed and use what you have. For 3-4 quads the TH was a must. (I've own a bumper pull and a FW TH.)
If you boon dock or spend 2-3 days at the track the larger tanks and built in generator are great. If you use it more for regular camping it is not a wise investment. You give up comfortable living space for "garage" area and gain 1,500-2,500 lbs. to drag around.
In my case the kids are grown and we do not ride as much as we use to. Sold the TH bought a nice TT. If we go somewhere overnight to ride a use a utility trailer and try to rent a cabin at or near the riding area.
