I have the same boat (85 H31) and have made the trip from SF to San Diego and Mexico several times. The boat is certainly capable, and as you have already recognized, the trip back is much harder.
I added a flexible water tank on the starboard side to give me an extra 25 gallons, and I carry an extra 12 gals of diesel in jerry cans. I also load on about 15 gallons of bottled water in various cubby holes under the seats. Have not had a problem with either fuel or water (although I generally single hand).
For planning purposes, I figure on 125 miles in a 24 hour period. Depending on your personal choice, from Seattle it can be a very manageable trip. There are good harbors about every 200 miles along the whole route, so you really don't need to sail more than 48 hours at a time.
I usually head 15-20 miles offshore for better wind, and to be outside the crab pots and inside the shipping lanes. It's probably 7-10 days to SF (depending on how much you stop). SF is a good place to linger and re-stock. Then it's 4-5 days to LA. The Ha-Ha rendezvouz is San Diego, but once you turn the corner at Pt Conception, you're into So Cal sailing (light air, warm weather) so you may as well enjoy it.
I think the longest sail for the Ha-Ha fleet is less than 48 hours, but you'll be sailing veterens by then.
Fair winds and following seas...
-Richard
s/v Discovery
San Francisco