Years ago (prior boat, not my Tug) I had a very mediocre experience with Cap Sante Marine -- though I know they are popular.
The local dealer is up in Bellingham (Bellingham Yachts). They partner with Northwest Diesel Power, also in Bellingham, for Volvo service. I had exceptional experiences with both, and it's a quick jaunt up to have it done. You might also ask Northwest Diesel Power and Bellingham Yachts if they work with a yard in Anacortes if you have to have it hauled and they can come down.
Also, you shouldn't need an annual haul out unless you plan to leave your boat on the hard! Haul-outs in the PNW can be done every 2-3 years, though some will stretch bottom paint to 4.
So, given that an annual service can be done in the water, if you don't need new bottom paint I'd call Pacific Power Group, which is a Volvo dealer. They serve the entire state of WA and will do annual service in your slip -- I don't know what the travel fee is to Anacortes, but they were several hundred dollars below other options in Seattle which more than made up for their travel fee. They are competent, reasonably priced, easy to work with. All of the things you want in a mechanic.