Indio/Palm Springs in the summer is HOT. Not just hot, but HOT. Ask the park what to expect in electric costs, they will probably have an average based on other residents. Swamp coolers do not work well in the desert, extreme heat and very low humidity and you get instant evaporation. Better to spend time and a little money on solar shielding. Make an insert for vents, get reflective shields, even the silver windshield shields, and fit them in every window. My friend purchased silvered reflective rolls from HomeDepot. If you have an RV frig, don't expect it to keep ice or ice cream. The Desert is Hot, sometimes not so hot, like your lucky when it is in the 90's.
Sorry for all the good news. Happy Trails.