This location is part of the quest "Blood Tide" where you have to hunt down the trapper leader that killed Cassie's husband.
There are tree sap buckets in the trees nearby the compound that you can collect. The double-storey house beside the lighthouse has a chem station in the attic and some lootable containers. At the base of the lighthouse, there's a weapon workbench.
In the top of the lighthouse itself, you’ll find Douglas, the trapper leader. Some of the notable items that you can find/ collect are the following:
You can use the boat lift from the top of the lighthouse to go back down quickly.
There will be more trappers in the dock area. There’s an Advanced terminal inside a boat cabin in the edge of the walkway near the lighthouse. In the small workshop west of the lighthouse, there’s a power armor frame, power armor station, and weapons workbench.
Head to the docks and loot the Mr. Gutsy wreck on a fishing net to the left and Douglas’s Trunk underwater in the adjacent fishing net. If you have his key, you'll be able to loot the trunk's contents.