So I think the best way to communicate what the film needs to look like or at least inspired to look like is to show photo references.
This is what the first sequence (Desert) will inspire to look like.
A large boulder will be on top of Sean.
The second sequence (Bridge) is where Jared and Sean helps Megan escapes from the river. Here's what the bridge should look like. Simple and stone built.
The third sequence (Tree) is where Aaron will be trapped in a tree, and the gang basically shakes him off the tree.
The fourth and last sequence (Tower) is where the band battles a shark. So the image is that the tower is in the middle of a giant lake on an island. Kinda like the image I've edited below.
And the boat is basically this. Its not real. Its a CUPBOARD CUT OUT!!!!!! The bridge will be a cupboard cut out as well. Nothing will be life size. Even the tree. Except few wide shots then it will be hand built miniatures for the green screen.
I hope this clears up more what the film will look like in the end.