Your sailing itinerary is going to make for a lot of time at sea. To get to Mexico, you are looking at at least two straight weeks at sea. If you do it in jumps, inertia and Wx could stretch that out to a month or easily two.
The sailing
route back to the PNW makes a stopover in
Hawaii a natural to break up the trip.
Budget three weeks to Hawaii and another three weeks back to the PNW. For a six month
cruise you are talking nearly half time that sailing on long ocean passages. For some that would be the whole reason for doing the trip. For most, having no time to hang out would kill the whole reason for the trip.
Trying to go up the coast is long slog to windward that's best considered as a
power boat trip with many breaks to wait for Wx.a
Weather is also a factor. October is the beginning of the winter storm pattern in the
North Pacific. You'd be lucky to get to SF without getting dusted. The other choice is to keep a Wx eye open and duck into one of the harbors along the coast between the Sound and
SF Bay when a storm threatens. I wouldn't worry about it below SF, I've made the trip twice, once in January, and it's been great sailing with reaching winds all the way. Hawaii has precious few natural
anchorages, none of which are safe in the big NW surf that occur very often over the winter and into April. You will be stuck with hanging out in harbors, most of which are not so hospitable here. The Hawaii Yacht Club used to give two weeks in the Ala Wai which is probably the best harbor if you think Hawaii is Waikiki. State
regulations allow one months stay in each harbor, on a space available basis, so you shouldn't have a problem finding some place to hang out. The sail back to the PNW is problematical in April. Besides being colder than most of us care to experience, the
North Pacific Wx is still prone to the winter storm front condition. The lows march across the North Pacific in 4-10 intervals which means you could get hit by as many as five different storms on the
Passage to Seattle. May would be a much better month to sail North and June or later prefered.
Your idea is not impossible. Just plan on doing a lot of
passage making and very little cruising and occasionally get your butt kicked by storms. The size of your boat is a big factor in doing the trip as you should be able to make better time than a smaller boat. It's still going to be a lot of days at sea, however.
Aloha
Peter O.