yes, I built the door, and installed the lock, to keep the artifacts, and things of value, safe. I didn't want some annoying explorer to go around breaking and vandalizing the Island's historical objects.
I think it would be better for the natives to have built all that. It opens up the possibility of other lightning-rod-related puzzles that you didn't (IC) create, and your present explanation is not really realistic. I can understand wanting to protect artifacts, but not locking them away where no one can (easily) find them. I think it would make more sense that you would put all the stuff behind glass or museum barriers in the beginning hut, or another building, where anyone could look at them but not vandalize them. Then, the secret door and chamber would actually be more meaningful, since they'd be actual discoveries of ancient stuff in themselves, instead of breaking and entering into a modern-day vault.
About the story: I know you want to keep it simple, so here is my simple proposal: a few people came to the island. They weren't actually native to the island, but I'll call them natives. They built the rods, the temple, the waterfall, the secret door, and a communal house (this may or may not be the link-in hut). They did things with the lightning rods that can be the puzzles (though they weren't meant to be puzzles at the time). They left after a while. Justintime9 wrote a link to Yinfara, added artifacts to the house and made it into more of a museum, and let people explore.
Having a jungle area solely for exploration is a good idea, if it is filled with interesting things, like what the pods should be.
