Size boat? For comfort? A 30-footer would be nice for single handing. For comfort the forced air heater is really nice. It typically rains a lot in Southeast Alaska so its nice to stay warm and dry. Yellow rain slickers - you'll live in them.
Can you do it in a smaller boat? Sure, but there is less comfort so there is a tradeoff. Take a look at an earlier thread back in 2014:
https://forums.sailboatowners.com/index.php?threads/crossing-georgia-straight.160509/#post-1100330
For a really good read, this is an interesting one: "North to Alaska by Oar, BIJABOJI", Betty Lowman Carey, Harbour Publishing Company, c 2004, 287 pages.
This is a story of Betty Carey who in
1937 when she was only
22 years old, rowed, by herself in an open dugout canoe, all the way from Garden Bay on Guemes Island (
near Anacortes, WA) to Ketchikan.
She had only a few charts and notes from talking to others familiar with the area.
No GPS. The country was, and most of it is still, unpopulated wilderness. Huge distances between any settlements (and still is).
No radio weather advisories. And she did the whole trip solo, by herself.
No sail and
no outboard,
just a pair of oars.
For trip planning, we did 2,222 miles in 77 days to Juneau via Wrangle and Sitka in our H35 and taking it easy. Had to wait several days for a paddle wheel to arrive from Datamarine in Mass. Radar was very helpful as was 435-ft of ground tackle. On the way back we arrived in Shearwater after the end of their dock blew away (I believe with boats attached). The 100+ft waves were between Cape St James and Cape Scott. The outside is better for sailing, inside for motoring. Lots of debris in the water. Going with company on a bigger boat, to me, would be a plus, especially if the company is a good cook, and can cook the salmon that you catch. Forced air heater will help keep the cook warm and make for a happy boat.
Oh, one sailboat from Idaho was T-boned out of Prince Rupert, in Dixon Entrance, by a highspeed aluminum (charter) sport fishing boat early one morning in the dark. The bow of the fishing boat went over and broke the boom on the sailboat. The skipper was in the cockpit and his wife down below.