Year round? Yea and no. Winter months can have few decent days, but depends on your tires and wether you can resist hitting go pedal as sunny usually equals cold.
Dealer support is non-existant. Most use a trusted nearby independat shop or do it themselves.
Skip all of the interstates and head to the coast and drive up 101 if time allows.
How long will you be in town? We have an autocross at the Shelton airport on the 8th which is also 5 minutes away from our best local track (The Ridge). About 2 hours south of Seattle.
I’m in Sammamish (2 lakes east of Seattle) and work in Seattle at the end of I-90. Let me know if you want to meet up and I’ll try to answer your other 999,997 questions. 😉