I'm in Moab a few times a year. I'm running a 3rd gen 4runner. Some of the climbs that are drivable would be scary, for me, in a short wheelbase 40. The length on my rig does hinder on some of the steps since the front and rear tires hit steps at the same time. Most trails in Moab are not loops so a rig that is still road legal is good. The summer heat can be 115*+. Moab has trails that you can drive with a stock Rav4 and some that you need a buggy. Most can be driven with a nicely modified rig.