With the C Dory, the weather you worry about the most on the outside is from the South. The prevailing winds are Northwesterly--and there can be some serious chop in some of the passes on entrances to sounds--as anywhere in the PNW, with wind against current. Our our circumnavgiation of Vancouver Island, we had only one day with serious weather from the South, were we sat out a day traveling. Granted we were in a larger, ocean crossing boat-, but we were looking at the weather from all sized boats and what was moving each day. Once inside of the sounds, the fetch is low enough that you should be able to move every day.
There are some really great places there--and much less traffic than on the inside, or even up in AK. We did pickup guests and a few supplies on the West side.
Enjoy the great trip!