I've been following the podcast and blog for Roz Savage, a woman from the UK who rowed across the Atlantic and is now rowing across the Pacific. Site and blog are here:

http://www.rozsavage.com/

She's growing sprouts so she has greens.

Biggest issue for her was early failure of her watermaker - apparently the hatch over it leaked and it corroded within days and was unrepairable.

Anyway, some interesting reading there, and in between all the other stories and posts, probably some useful information on longer-term survival.