Im in the planning stages for my next tour. Looking to start in Alaska down to California. Not really to worried about making a route through the west coast of the US because ill most likely pick up the maps from ACA but not really sure how to make a route through alaska and canada. Ive toyed around with google maps making routes but just seems like there is huge stretch's of no towns or services. Not really worried about hotels as i will be camping and making my own food majority of the time but being able to find water and food is my main concern. If anyone has any experience with a similar route that could share some info thatd be great! This will be my second long distance tour i did the northern tier back in 2010 so im not to new the touring scene

I'd look through the journals at crazyguyonabike.com, and search for "Alaska Highway". Though I did get the impression from some journals that the scenery on the highway does not change much, and maybe combining it with some travel on the Inside Passage would break the monotony. Though I'd expect getting chased by wolves and bears would tend to make things more exciting.

ACA is bringing back the North Star for 2014 (Missoula to Anchorage). I rode it with them in 1989 when Adventure Cycling was Bikecentenniel. No Alaska Highway, ACA likes the roads less travelled 8-) We didn't have maps, just a little booklet. You might contact them to see if they've got anything you can use.

I can comment a bit for the route in Canada, I highly suggest taking the Cassiar Highway (#37), then you can either go to Prince Rupert and ferry to Port Hardy or Vancouver or go to Prince George and pick a route going south from there.
The Cassiar has no services but you can get some wi-fi if you stay at the lodges on the way (I didn't). The scenery is amazing and definitely worth it!
In terms of services/grocery stores, from Whitehorse:
~200km Teslin (small store, not too much variety but it has good prices. Stock up for the Cassiar here unless you are making 20km detour to Watson lake)
~400km after teslin, is Dease Lake (good store - u can find fruit)
~83km to Iskut (has store)
~150km to Bell 2 lodge (has store)
~100km to Meziadin junction (if u take detour, there are lots of services in Stewart/Hayder), if you dont detour, the campground has a small store - with surprisingly low prices but not big selection
From there (200km) there's not much until New Hazelton (Kitwanga and another small village before it have a store)

well if you decide to do this route and have more questions, PM me

You will probably meet other cyclists too, I met about 10 people who had taken that route when I was heading north.

I've ridden from Fairbanks to San Fransisco via the Alaskan Hwy, have traveled the Cassiar Hwy, and cycled from Prince Rupert to Prince George and south. As "iohan.gue" states, the Cassier is quite scenic, but remote with little services for bicycles. The Alaskan Hwy also has very good scenery and has more and varied services. The road surface is also better. The ride between Prince Rupert and Kitwanga, the south end of the Cassiar Hwy, is very scenic for most of it's 90 miles. If going through Prince George, there are plenty of towns and services all the way south and you travel through less scenic country until you reach Cache Creek. Riding through the Thompson and Fraser River Canyons is very scenic until close to the Washington border. I have traveled on just about every road in British Columbia, so if you have any questions feel free to pm me and I'll try to answer them.