RE: Hawaii: Which island and which period?
i would recommend just showing up on maui, get a month stay in a hostel then watch the notice boards at mana foods and classifieds for cheap rentals in paia, kuau or haiku, or cheaper in pukalani.
there's no way to guarantee 5 consecutive months of wind and waves on maui. spring and fall are both good, spring maybe a bit better. if you want to surf without wind then overlap your stay into winter, if you would prefer high wind, flat water freetyle or slalom sailing then stay for part of the summer.
there are zero waves in the summer and high wind everyday, that's the weather that's most consistent over there.