I make a lot of drives between Bellevue and Neah Bay. My all time best drive time is exact to the minute, between the two routes. The key would be to time the Edmonds-Kingston run perfectly, and time wise, both routes will take approximately the same amount of time.
South to Gig Harbor, then to the Hood Canal BR is about 65 more miles total driving distance than taking the ferry.
(For me, the Bainbridge run, and the Kingston run usually take the same time as well, traffic dependent.)
Pick your poision; ferry costs, or fuel costs.
(When towing, I go down and around exclusively.)