There's a Dwarf doctor on one of the beaches. What does she need? Medical Supplies. So she could give you a quest to bring her some. There could be a couple ways to complete that quest. The difficult way would be to infiltrate Fort Joy and visit the BRAND NEW TOP FLOOR which houses the barracks, mess hall, kitchen, infirmary, and storage areas... but is also patrolled and has level 3-5 soldiers.
The medical supplies from there would solve the quest. There's also a way to craft supplies:
Cloth Scraps = Prison Clothing + Knife
Bandages = Alcohol + Cloth Scraps
Needle and Thread = Needle + Thread
Partial Surgical Kit = Needle and Thread + Bandages
Surgical Kit = Partial Surgical Kit + Anesthetic (AKA "Hammer")
Splint Kit = Small Branches + Rope
The kits would have no use for the players. (Well maybe it could be that a Surgical Kit cures Bleeding, Splint Kit cures Crippled.) The prisoners (especially the Doctor) and the Seekers would pay decently for them.
Even if the extra floor doesn't get added, medical supply kits could be added elsewhere around the fort.
