I doubt there will be enough snow for snow mobiles, just enough to be annoying on the hike in.
To clarify on the gradient- most of the altitude loss that I mentioned in my prior post is hiking down to the river. The hike down the ridge would reach the river at 10,200ft, and the confluence is at just under 9,800 feet, leaving 400 ft drop in 6 miles. Looks like there is one canyon section, but the rest looks like windy medow stream.
I heard a great quote the other night attributed to one of the members of the Tsang Po expedition; after looking at satalite images of the Tsang Po, he commented- "You know you're in trouble when you are scouting from space!"
I might paraphrase that to say "You know you're in trouble when you're scouting on a topo!"
I take no responsibility whatsoever for mindless blathering and speculation based upon brown squiggly lines!