Andrea, the generator will run off the gas tank that the van uses.
As far as effecting your MPG I would say its pretty minimal.
Ok when I bought my van I used my credit union for the loan and since I have used them in the past on other loans it was no big deal....
As for picking up your van it is easy, after all the paper work is done Deric will give you a vehicle permit (its a little different then a 30 day tag, but its what Nevada uses.)
Since I had driven out there and had a trade in I just used my tag off my trade in for the drive back.
Your current insurance, if its full coverage will cover you until you get back home...but double check this ok, each state is a little different on this.
And of course the bank wants you to have full coverage insurance on it.
So, I hope this has helped?