Where do you find water

Believe it or not, ranger stations will often let you fill up. Tip: before asking about the water, first go to the front desk and buy a forest map (which are very useful).

Then ask about the water. ;)

Be sure to carry a Water Thief (bad name, good gizmo). It slips over unthreaded faucets so you can connect your hose.

Not always, but often the same places offering a dump station have a potable hose outlet nearby.
If you havent used it, Sani Dumps may help with both task.