For a one time trip I can understand what you are talking about. How long is your stay there? You may be able to rent a generator for that time and save a lot of money.
The park is above 8000 ft so there may be a chance you will not need AC, then again I've seen it 80 in the shade at 10,000 ft so who knows. (record setting year)
You can keep you battery charged up with a pair of battery cables off your truck. It wont be the most efficient but it will cost a lot less. We did it for a week when we first started while needing the furnace nightly.
You could get a few inexpensive ebay LEDs to replace your most used light while there. $10 could save a lot of battery. Cob style go in and out like a regular bulb.