Some 4x4s can be flat-towed. For example the '00 Nissan Frontier Crewcab (traded-in for '03 Tundra). It went many miles, in Park no less, right behind the old Winnebago. No dolly required, just towbar stuff. (But braking adaptations were in place.)
Of course, the transfer case having a neutral was the key.
The Nissan people said just start it up & run it after each 200 miles or so just to be safe. Never had a problem, it ran 89,000 hard miles after that just fine.