I did this route in reverse of yours via Dawson just this June, 21 days from where I am in Monterey CA, your gas cost is just about right, camping in Canada was great, Cassiar RV Park near Kitwanga was GREAT, Bonanza gold in Dawson was GREAT, Glenallen Northern nights GREAT spot, Tok Sourdough Campground ($$$$), I stayed in a Hostel in Portland and moteled in Hope Canada, Rancheria Motel if raining if not get a camping space.
One stretch which was very scary was an 6mi of loose 2in gravel, Haines Junction to Whitehorse, It may be paved when you get there but be aware.
Longest stretch for gas was Kitwanga to Bell2, 160 miles. Research your gas mileage and carry a 1gal if you can, just in case, I did not need it, but you never know if the station is open or closed, specially now days.
Have a great ride.
achtung3 screwed with this post 11-14-2012 at 12:57 AM