Finding stars can be lucrative once sims find 25+ of them. On an island I'd think fishing would be the obvious choice. Can your sims travel? Tomb exploring can make lots of money from relics, gems, and metals. Day jobs at university can be worth a bundle. If there are dive lots in the world and you have IP, deepwater fishing and looting chests can make lots of money, especially if you consign everything. My current household owns a resort which is pulling in about 13k a day. Might not make sense on a crashed island though.
