Hydralic jacks are a tempting reason to bring the motorhome. Also as you point out, most toy haulers are much more useful once unloaded, and many places they do not want to see a quad ouside.
Fuel mileage will be much better with the diesel though. Also you will have a sightseeing vehicle. One huge advantage of a fifth wheel is you don't have to break camp in the RV to go out sightseeing. So bringing out things like flowers, or setting up the awning or leaving dishes in the sink is OK in the fifth wheel, while the RV would need all these things put away before going sightseeing.
Just a couple more things to think about.
150,000 miles is not to much for a Allison DM truck. I would not be worried about the mileage.
Fred.
Money can't buy happiness but somehow it's more comfortable to cry in a
Porsche or Country Coach!
If there's a WILL, I want to be in it!
I havn't been everywhere, but it's on my list.
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