I've been out that way twice, for a couple weeks each time. It was on a 76ft megayacht though.... so a little different that what you're planning.
Clearing customs is something to plan. It would be nice to launch from Neah Bay and go up north, but I don't think that's feasible. More likely you'll be clearing in Victoria and staying close to the north side of the straits. Port renfero and Sooke are good places to stop. Plan your trip around the corner with the tides but take caution because an ebb and an onshore wind will create ugliness at the corner. Give it a wide berth.
There IS a lot of fog up that way in September. If you don't have radar and you postpone your trip, I would consider investing in radar before you go. We had it move in on us and sock us in very quickly both time we were up there (july and september).
Study the chart of the broken group carefully. While it is a haven for kayakers, there are only 2 or 3 anchorages in that group for a sailboat. The nearby towns are fun though, the fishing in the area is AWESOME and just north is Hot Springs Cove which is worth visiting. It's a hot spring that flows down several rock pools and mixes with ocean water. Each pool is cooler than the one above.
Would you consider sailing at night on the way up? It makes the ships easy to see unless there's fog. If there's fog at night (which there often is) you're screwed.