Hey Mac, a note on your opening post. my propane tank/furnace, used very carefully in my extra-insulated van, with the top down and reflectix up, will still only hold survival temps for at best 5 or 6 days in the climate you describe. YMMV.
I bet you really are experiencing "climate-shock" from your changed location. I experience a major physical change when I leave the hot and ridiculously-humid South and go to the hot and ridiculously-arid West... I dry out like jerky (insert wisecracks here) and no amount of water seems to help... 'course beer doesn't help, only makes it worse.
My most unexpected lesson about these vans is the vast difference from tent camping... I just can't go back now.
And, the unexpected money these evil machines soak up
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'95 SMB E350 Quigley 7.3
https://www.taylorarts.com
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"... do they ooch apart in the night?" -Dia