We also liked launching our trailer boats in Bellingham.
Our preference is for the more remote and less populated (by humans - more populated by other critters) areas. So we tend to head north, spending a few days in the San Juans, then on into BC. If you limit yourself to 30-45 days, I'd say trying to make it to SE Alaska doesn't make much sense unless you are willing to rush it, covering many miles most days, and missing much of the beauty all around you. Mid May through September is a good time frame for heading all the way up through SE Alaska and back.
If we're not in a hurry to meet a flight somewhere, we find that traveling an average of 30-40 nm/day works well for us. Or even less if we do a lot of fishing, dinghy exploring, or shore trips. If that modest sort of rate works for you, you might choose to stay south of Cape Caution. You could go further north in BC, but rounding Cape Caution (sometimes a pretty challenging bit of open water) could involve significant weather delays, especially in spring or fall.
Another thought: you could spend 30-45 days and make the most of the trip up to Ketchikan, leave the boat there for the grandkid fix, and come back later to head south. Or, you could tow up to Prince Rupert and head north into SE Alaska from there - this was our strategy for many summer cruises.
You might want to pick up the Hemingway/Douglass Exploring series cruising guides, BC South Coast, BC North Coast, and SE Alaska. Waggoner tends to be more marina-oriented, and the Douglass guides more anchorage-oriented. If your chartplotter doesn't have detailed current timings, get a copy of "Ports and Passes", the excellent tide and currrents reference for BC.
If you head north in BC past Campbell River and Desolation Sound, make sure you study the cruising guides on the tidal rapids in the squeeze between Vancouver Island and the mainland. You will need to time them appropriately (though not necessarily exactly at slack current - 2 or 3 knots is usually no trouble).
Crossing the Queen (Queen Charlotte Sound) around Cape Caution to the BC North Coast, can be quite a challenge. Of course you don't want to be out there when the wind is howling. In reasonable wind, say not much more than 15 knots, the key is to consider wind direction vs tidal current. If they are opposed, waves get as much as twice as tall as you might expect, and much steeper. One of the worst situations is westerly wind opposing the tide ebbing out of Queen Charlotte Strait. Or the opposite combination.
If you do round Cape Caution, be sure to know when the Nakwakto Rapids is ebbing. In a strong ebb (timing of which is quite different from that of other locations), the current from Slingsby Channel can be felt miles out into Queen Charlotte Sound. If opposed by a westerly wind, there will be big waves, even standing waves in the mouth of Slingsby Channel. I'd stay at least 2-3 miles west of the Cape if the rapids are on a strong ebb. We got rolling pretty good even 3 miles out last June.
Happy to share more,
