Did you say "winter"?
I've ridden through Pagosa Springs a number of times, but in warmer seasons.
Yes, the traffic is considerable - fair shoulders, perhaps widened since I rode.
US 160 west of town is busiest, US 160 over Wolf Creek Pass is also pretty busy.
US 84 heading into New Mexico has the least traffic.
But there will almost certainly be snow - and shoulders are often unplowed.
Pagosa has also gotten quite pricey. 25 years ago it was still undiscovered.

As for Seattle, I would suggest a kayak.