(sigh)
Water usage . . . Had a friend once who managed to hold herself down to 3 gallons of water a day. With those 3 gallons, she did all her cooking, dishes, bathed, flushed the toilet, etc. At the other end of things, when I was studying water & waste water management years go, I learned that the majority of building codes called for sizing a septic system based upon the assumption of 100 gallons per day per person. Expect to use somewhere in that 3 to 100 gallon per day range.
Likewise, fuel for your generator to run the one or two 13,500 Btu or 15,000 Btu air conditioners in your rig for 6 to 12 hours a day in 85 degree to 120 degree weather, um, well, you do the math.
I'm sorry, but estimating any of that stuff requires a LOT more information than we have to calculate. Things like, how dedicated are you to conserving water/fuel, how hot is it, how many ACs, of what size, how many of you are there, etc. are critical, and we have no clue.