The Port Townsend ferry is fun and a must do! Yup, def. avoid going the long way down through Seattle to Olympia and all the way back up the west side of Hood Canal - the traffic through Seattle is pretty bad and can be hard on a TV and trailer esp. in rush hour. We normally avoid going through or around Seattle and take the ferry and 101 south out of Port Townsend instead. Plan on spending a little time in the old downtown area of Port Townsend.
'Course, you could take the ferry from Anacortes to Vancouver Island or go up into BC and take a ferry to Vancouver Island and then take the ferry from Victoria to Port Angeles. :B
The narrow road through Deception Pass is nothing. I could drive back and forth all day long there. There's a lot worse in some places out there. Just watch out that you don't flatten a tourist darting across the road on the bridge. :E