If you are going to spend a lot of time sitting (not moving) in the desert, you are better off not buying a diesel pusher. The advantage of a DP is moving, not staying in the same place. If you will be moving every week or two, buy a MH, gas or diesel.
Just an FYI, our trailer could be dragged to more places than our class A can go. The weight of the class A (22K+ lbs.) makes driving in sand, mud, and soft clay much more difficult (and risky). There is no way our jeep can pull our bus out of a quagmire but the F250 we had could pull the trailer out of anything, from the back or the winch in front, which ever worked better.
We also are more timid driving the A on truly horrible roads that we would drag our tt on - we didn't have to listen to all the noises in the tt; in the class A, it sounds like a major earthquake (which I guess it is).
If you want to be more remote, a tow behind is easier. If you aren't wandering very far off the road, a class A works.