We've got a 24' stacker that has a 4,000 lb. full lift in it. We carry one car, a harley trike and a harley dresser. We have reservations this summer to see Yellowstone, the Tetons, Moab and Durango with the stacker. Having said that if on any given trip I can get away just towing the Tahoe or Avalanche I will.
We are pulling it with a 550 HP (up from the standard 515) Detroit. I know it's back there. Get the biggest engine you can and get the lightest and shortest stacker you can. ATC has some pretty good deals on 24' stackers.
Our MH is 45' and while we don't full time in it, we spend approx. 8 months ear in it. wouldn't go shorter.
At some CG's you may have to drop the stacker. It really helps if one of your vehicles in the stacker can be used to drop it (empty).