"DannyD." wrote:

snip
The sloshing tipping over the truck seems to me to be a very
real concern that I hadn't considered, because, there is no
guardrail, and you're going down a slope that doesn't end
for thousands of vertical feet, so, it would behoove us to
better understand the sloshing effect on a pickup truck filled
with a 1,000 gallons of water in a tank.

You just need to make sure the tank is full. A full tank will not
slosh very much if at all. You also want the lowest and flattest tank
that will fit to keep the center of gravity as low as possible.
--
Jim Rusling
More or Less Retired
Mustang, OK
My local Weather http://www.wunderground.com/weathers...p?ID=KOKMUSTA4