I hauled 2 cats simultaneously, from 1997 up thru last year, with a One Ton dual wheel GMC 4 wheel drive turbodiesel. I put one on the truck and trailered the second machine. With 3 drivers we made it from Seattle to Yellowstone in about 15 hours. It's about 1200 Miles. It's best to have large fuel tanks for the extended runs. I retrofitted the one ton with AIR BAGS to give it additional stability. The truck was rated to carry 5500 Lbs, and all of my snow cats weighed well under that even with the additional trailer tonge weight. A Diesel with high torque and a turbocharger for the high elevations is very desireable. The Dodge, Ford, and GM's all work well for this application, but the GM Rides the best with it's fully independant front end. Even though the Air Bags were not required, they sure improved the ride.
Always carry Chains even if your tow rig is 4 wheel drive. As you get into Snow Park roads that are narrow and Icy don't blow off using them. Just because you have 4 wheel drive and a snow cat or two doesn't mean you won't slide it into a ditch, other idiot on-coming snowmobiler, or the guide Rail. As soon as it looks shakey, put those chains on! I also had a 30 ft. triple axel and hauled 3 at a time to the VW Shows, so it can be done, with care.