Chris,
The trip across from Campbell River to Desolation Sound is not a big deal. Just be careful going around Cape Mudge if strong winds are going against a big tide rip.....not fun. All said, 99% of our trips over and back have been a piece of cake. We were caught in that situation once before and, as I said, it was not fun but our 22 cruiser handled it like a pro.
Port McNeil to Desolation is not an option.......way too far backtracking back southward. Comox to Desolation is something you may want to consider.......greater distance with more open water to cross but a bit shorter of a drive by road.
Cheers, :beer
Tom