My suggestion is to have a small area in the island be setup as a "boss camp". This area can't be build on.
But it can randomly generate some bandit camps, or boss camp. Maybe on a daily basis. so you can only fight it once a day.
So this is something you can at least have fun with each day. And random daily drop from beating the camps.
Possibly the top left corner of the map can be modified since there are no buildable areas there.
