Inner stay helpful
Charlie - doesn't sound like a fun trip! A comment about the forestay holding up the rig - looking at one of the slide show pictures there is an inner stay so that should be helpful if the main is reefed and provided that if the sprit fails it doesn't compromise the innerstay deck attach point.
Bowsprit: Never used it before but would something like "Git"-Rot help any on it?
http://www.boatlife.com/how-to-git-rot Being up-side-down it would be hard to use but maybe a thin fiberglass shell over the rotten area and then inject the Git-Rot stuff however it is supposed to be done.
Pilothouse windows: Looking at the interior shots, it doesn't look like there is a way to close off the pilothouse cabin from the rest of the inside of the boat. If this is the case then be careful about taking any blue water that will compromise the windows. A couple years ago there was a Hans Christian going down the coast and off the Oregon/California coast they took a hit which broke through the window and it wasn't long before the boat sank like a rock. Well, with all that lead in the keel, probably faster than a rock. The pilothouse cabin was wide open to the inside cabins.
Rudder & Strut: Also several years ago I had my boat hauled out next to a Cal 50 and a recently retired architect and his wife were doing the finishing touches on their boat before they went down to Mexico and the South Pacific. Hummm.... the propeller shaft strut just broke off at the hull surface! It was bronze and old. The flat part of the strut was recessed and puttied over to make the surface smooth. Anyway, it took them a while and a lot of $$$ to get a new part cast and installed. I would say the same thing would apply to any of the rudder parts, too. These would be good parts to check on an older boat or if one takes a chance, do it very carefully. Trouble comes in bunches and one wouldn't want to be going into, say, Crescent City while riding a surf and have "something" go.
Is that a Venus binnacle at the wheel???
Edit: P.S., maybe it was a Columbia 50 vice Cal 50. Probably was.
Hope you have a good trip. I know it will be interesting - guaranteed!