Let’s see....
They are lost on an island and discover that some international company is going to doing something evil with the prestine wilderness. Something like clubbing the orangatangs, to make coats for Republicans.
You need a guest character of course. A person from the future appears on the island and warns the castaways that the lack of orangatangs in the future means the Earth is doomed (played by Sean Penn).
The castaways make weapons out of coconuts and bamboo and along with the noble and sentient orangatangs defeat the colonialist imperialists.
As night falls, in the glow of the burning capatalist huts, the castaways decide to stay on the island, join PETA, and live in peace with the monkeys, forever.
I’d rather Ron Zombie would write the script and direct.
Ginger, Mary Ann and Gilligan are college kids from California on spring break. The millionaire is an old fogey with a young trophy wife. The professor is a lusty middle aged guy that is with the kids. And the Skipper is trying to change his ways after escaping from the Honolulu state mental hospital. But after the shipwreck he returns to his old ways of murder and torture.
Tormented by his past and seduced by his horrific fantasies he stalks the islanders one by one. The millionaire has to go first so the bulk of the islanders are hotties.
The professor helps the kids to construct weapons and traps in an attempt to capture the skipper, but this only makes him more murderous. The trophy wife dies in one of those traps after they mistakingly think they have caught the skipper.
Lots of night time running through the palm trees using a steady cam.
The professor is next, some really gruesome disembowelment, which leaves Gilligan and the two scantily clad girls on their own. More night time chases. Ginger is the next victom. Some gratuitous nudity as the skipper feasts hungrily on her flesh.
Gilligan and Mary Ann are chased to the top of the island’s volcano and after a fierce battle the skipper falls into the lava far below.
The two, now lovers, run to the shore to greet a rescue ship. When they get to the beach the rescuers have already landed. The last scene shows that the ‘rescuers’ are actually people who had escaped the mental hospital with the skipper. The one holding Gilligan says “You kills our friend!” and lops off his head. Fini.