Getting to Anacortes:
You can take a shuttle from the SeaTac Airport or take Amtrak to Mount Vernon and a connecting bus.
But since you're only giving yourself two months, you won't have time to see the beauty of the San Juans.
Summer - but not as hot as further south - in fact, quite pleasant.
If you plan to ride west to east, early to mid June can be tricky in the Cascades & Rockies.
You have to be kidding. The Northern Tier is 4300 miles.
That's 75 miles per day for 60 days - no bad weather, no breaks, no breakdowns. Uh-uh.