How much time are you allocating for the trip? Starting when - about May 1? Earlier?
When do you want to fly out of SFO? When you say "messenger activity in the summer" - I'm guessing you plan to be back on the islands by July 4th?

PS - You do know than in a lot of the area you are biking thru - vegetarian means a pot of beans with a hunk o' pork floating around in it. And vegan - I suspect some folks may respond - "Yup, I got me a '44 and a shotgun - but I ain't never heard of a V-gun - must be one of them new-fangled thangs." Just a heads up.