Visible crew/equipment: When Chuck is crawling on the floor of the plane to reach the watch, the compartment behind him where the raft was stored, you can see the stairs leading down into the set. (00:23:40)
Visible crew/equipment: When he collects coconuts for the first time if you look in the lower right corner you can see some sort of light flashing, I'm guessing maybe a light meter or possibly a two-way radio that the crew was using.
Answer: Cast Away was filmed on an island called Monuriki. It's part of a group of islands called the Mamanuca Islands, in Fiji.