TO @leporidae: The Alaska Highway (aka ALCAN Hwy) is totally paved from Mile Marker “0” in Dawson Creek, BC thru to Delta Junction, AK (Mile Marker 1422)… although you can then proceed onto Fairbanks, AK… which has a “corresponding” Mile Marker listed as 1522 (again that road… the Richardson Hwy, is also paved)
Likewise the route from Washington thru Canada, most commonly taken northward… be that thru Alberta or British Columbia onto Dawson Creek would also feature paved roads.
Where you run into issues with Rental Cars is if you decide to take your vehicle onto unpaved roads… and there are definitely some to be found in both these parts of Canada and the USA. Just make a point of not venturing onto them when you are out exploring / day tripping.
For the record, Alaska is a long jaunt from the Lower 48.
In that you have to go thru a large portion of Canada BEFORE you even make it to the Alaska Border.
Seattle WA to Dawson Creek BC, via British Columbia is aprox 800 Miles (15-1/4 Hours Driving Time). Then the Alaska Hwy up to Delta Junction, AK another aprox 28 Hours Driving Time… and onto Fairbanks… add on another 1-3/4 Hours.
So just in driving (not stopping and sightseeing along the way) = aprox 2269 Miles and 45 Hours of Driving Time ONE WAY !!
GOOGLE MAPS – Seattle WA to Fairbanks AK = http://goo.gl/maps/fdTUW
OR about the equivalent distance from Seattle WA to Toledo, OH (except that that drive is about 10 Hours shorter, because the Interstates in the lower 48 are much better)
If you go via Alberta and the Canadian Rockies… That extends to trip to aprox 2487 Miles and 49 Hours of Driving Time… again ONE WAY.
GOOGLE MAPS – Seattle WA to Fairbanks AK (via the Rockies) = http://goo.gl/maps/E4c7L
Plus lets face it, if you are going to do this once-in-a-lifetime trip… you’ll want to spend plenty of time enroute seeing all the amazing geographic sites… the scenery truly being out of this world !! So you better have WEEKS of free time / vacation time to do so (one of the reason that Alaska vacations are soooo popular with Retirees and College Kids… who don’t have as many things to tie them to home as the rest of us)
Also, you should note that if you self-drive… there is ONLY ONE ROAD up and back … the Alaska Highway… so you will be doing the same route on the return.
All of these are reasons WHY so many people opt to fly to Alaska. Or take a one-way cruise, and then do a organized land-tour that takes them the other direction (again as you said in your OP… Expensive options)
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If you haven’t the time or the funds needed to do this adventure the way you envisioned… you might want to still consider a Canadian Honeymoon instead. The Provinces of British Columbia and Alberta are GORGEOUS… and have much to offer. One could easily spend a week or two exploring either one.
Hope this helps,
PS… If you need more insight into BC or Alberta, just ask… as I have been to both (haven’t been to Alaska yet… but it is on my MUST DO list after I retire… have had Friends & Family go and they said it was SPECTACULAR)