While it is true that a hendheld GPS will use up batteries, Why would you leave it on at sea? Once the position is checked, it takes about three minutes, turn it off. We checked our position no more than three times a day crossing the pacific and only had the gps on for more than a few minutes at a time while approaching Cape Flattery. Our primary unit is a Garmin GPS 76. We changed the batteries twice in 55 days and put in fresh as we entered the Strait of juan de Fuca because of the fog. As my flight instructor admonished me: "Don't stare at the instruments, look where you're going!"
Windvanes: Depends on the boat. We decided we don't need one because Lealea proved that she will hold a course for days at a time without attention, as you mentioned, given proper sail trim and a shock cord on the tiller.
Alcohol cooker: To each his own. Laura does most of the cooking and she likes the simple little two burner Origo we have. I can tell you I haven't suffered from lack of tasty meals either
Dingy: Yep, its a problem all right
Malie ke kai