Obviously boots on the ground is the best source of information but as in your case, that's pretty much out of the equation. Google Maps is usually pretty good but again, the west has been going through the worst droughts in many a year, so as for me, I really wouldn't trust too much of anything that can't be verified. Calls to the USFS, Game and Fish Departments, BLM land managers, etc. might be something to look into. Until I located a good water source in the area I was hunting, I would also carry enough water with me to last a couple of days while hunting, just in case.