7500w is more than enough to power everything in the rig. Will have to look at plug configuration on genny. You'll want to use a 30 amp 110v plug on generator and adapt it to an rv plug connection if needed.
Most funrunners I've seen have a magnatek converter so not real fast at recharging batteries. so plan on running a few hours a day to keep batts up. Preferably with meals or middle of day so not to annoy other campers if the genny is loud.
I'd ask to have fridge turned on 24hrs before you pick up and pre cool food you'll be putting in it. Were it me renting, I'd take genny with me to pick up to insure air, microwave work before I got out to the desert.
Find out the water tank capacity so you don't run out.
Make sure it has a good spare tire and you have needed tools to change it.
I'd ask for a list of what trailer comes with, pots, pans, utensils,toiletries? so you know what to bring.
Have a blast :B