I would leave your motorhome plugged in, air on, fridge on electric, etc. I wouldn't want the wood to be subject to 100+ temps inside, especially, in a dry climate.
Ours is in storage right now for about 2 months. It's in a garage with 30 amp service. I have one air set at 90 and I put three small buckets of water around to keep the humidity up (located in the desert).
I also put extra water in the toilet as it will evaporate by the time we get back. I close all the drains in the sinks and put a rubber cover over the shower drain to help against evaporation.
MM.