Weather, I think a few storms would make it more interesting, some cargo netting to tie everything down? Also when breaking items down, you would get back a percentage of the materials. Maybe an occasional bird or two flying by, or landing on the raft to kill for meat? Islands or Ships in the distance that you never seem to reach that would fade over the horizon. A radio, make a battery out of salt water copper and zinc, that would be a rare item in a barrel. Once built you could hear music depending on where you are in the ocean, Hawaiian, Asian Pacific, Australia or New Zealand. You have Palms and palm fronds so that would make it in the Pacific Ocean.