Stormin Mormon wrote, on Sat, 28 Jun 2014 07:53:30 -0400:

So, you'd best to budget a LOT for motor fuel on
your project. Driving water uphill is not going to
be the same as one frail gramma in a Prius. Might
get dual 1,000 gal tanks, one white for potable
water, other red for gasoline.

I always wondered how much of that lost fuel mileage you
get back on the downhill drive, which is done essentially in
neutral for the entire 5 miles.

I realize it won't exactly cancel out, but, essentially you
get 100mpg (or whatever) on the downhill drive; while you
probably get something like half your city mpg on the uphill
climb.