You don't really have to go out of your way for this one, I found that at every island when you run around grabbing the stuff, just build a pile for each thing.
I usually had a pile for sticks, palm fronds, fibrous material, rocks, and occasionally the logs(if I was staying there long enough to do some building or refill water bottles) on each island, so 5 piles per island only means 20 islands to explore.