The first thing you should really look at is why you are going through 60 gallons in a week. Truck Camper owners do a lot more with less than you have. I full time in my truck camper and have been going for over 8 years and average about 17 gal a week in potable water. Dry camping you are in areas where water is readily available, start looking at easier ways to acquire water, as well as disposing your grey and black tanks. Simply conserving just might cure your issue and not need expensive change of RV.
Could you share in what you are using your 60 gals of potable water on for a week?
b