Both George Erickson and the couple in the Maule from Georgia came up the inside passage from the Seattle area, which wouldn't be my first choice, due to weather, fuel, and salt water, and would be a long ways out of the way from Bozeman.
The Canadian government produces a document called the "Water Aerodrome Supplement" It is a very comprehensive document containing information on water landing areas, particularly ones with services, in Canada.
Take a look at the Alaska Highway route, either in the Alaska Airmen's book, or on a strip chart, then figure out your stops from the Water Aerodrome Supplement.
Once you leave Whitehorse (a previous respondent was correct, this is a river stop, so you need to understand moving water) you can clear Customs at Yarger Lake, which is a few miles east of Northway. You notify Customs ahead of time (of course) and they'll meet you there. There's no fuel there, though, but the Lodge in Northway will deliver gas there, I believe.
That'll get you into Alaska, from there, your imagination, avgas, weather and your wallet are your only limitations.
In Fairbanks, we have a great floatplane facility, and if you wanted to leave a plane for a few weeks, this would be a good place to do so. One of the operators here could yard the plane out with a trailer, and leave it in a tiedown till you return. Good airline connections to and from here, though probably not quite as good as ANC.
Course, Anchorage is a very nice city, and it's only about 100 miles from Alaska.
Well, that oughta get a rise.
Water Aerodrome Supplement can be ordered through Aeronautical Information Services, Transport Canada, Place de Ville, Ottawa, Ontario, Canada, K1A 9Z9, or the Department of Natural Resources, Canada, Canada Centre for Mapping. It also contains a tremendous amount of information on Canadian flight operations.
Also acquire a copy of the Supplement, Alaska, from any aeronautical mapping source office. It offers much the same information (landing sites, fuel availability, etc.) for Alaska. Sporty's Pilot Shop can probably sell you both the latest Canadian Water Aerodrome Supplement (make certain you ask for the WATER aerodrome supplement-there's a land aerodrome supplement as well) , and Alaska Supplement, as well as any other charts you may want.
MTV