Just as a FYI....
I've cruised up to Roche on several occasions in a 2010 R-25 Classic (Edmonds to Roche), a 2016 R-21 EC (trailered to Anacortes and then to Roche), and a 2018 R27/OB (Edmonds to Roche via Deception pass without any regards to tide/current at the pass) --- all done in one day. The R25 and R21EC took the longest as you would expect. The R27/OB going at close to full speed (fairly calm seas) took around 3 hrs at best going either way using shortest route.
I now have the 2019 R29 CB NW Edition but will not be going to Roche for the RT's GTG this year.
IMO (I've made all these routes over the past years)
1) Shortest/fastest: From Seattle or Edmonds going up Admiralty Inlet to Port Townsend, then across the 'open' Juan de Fuca Strait to go between Lopez Island and San Juan Island into Griffin Bay, then on up to swing past Friday Harbor, then on up to Roche is quite likely the shortest and fastest route to take. The Juan de Fuca Strait weather is the one to watch out for.
2) A slower route would be to go up through Saratoga Passage up to Deception Pass and then on up across Rosario Strait to Lopez Pass and then into to Lopez Sound, then continue up east side, and of Lopez Island to Harney Channel, then make your way west to Deer Harbor / North Pass, then up to Roche via San Juan Channel and Spieden Channel then round over to Roche.
3) A slower (more time consuming)
and safer route is to go up through Saratoga Passage up to Skagit Bay and then pass Goat Island and take the 1 hr long ride north along the Swinomish Channel, passing La Conner (no wake speed of around 4-5 kts) on up to Anacortes and into Guemes Channel, then going west and over to Thatcher Pass, then onto and through Harney Channel, then make your way west to Deer Harbor / North Pass, then up to Roche via San Juan Channel and Spieden Channel then round over to Roche. If you have time break the trip up into two stretches; Seattle/Edmonds to La Conner and stay the night at Port of Skagit in La Conner or at Cap Sante Anacortes (if there on Wed drop in on the Pizza party that others have traditionally been to -- Ref here ->
http://www.tugnuts.com/viewtopic.php?f=4&t=13474&p=91202&hilit=Nellie#p91202).
In all cases, have sufficient fuel on board, and check the weather before leaving and while cruising to Roche.
Enjoy the Roche Harbour RT GTG.