Make the indoor plan concrete
The Port Isabel Historical Museum presents regional history and publishes material about local people, coastal life and historical storms. Call for current public visiting hours before leaving: the website also contains past programs whose dates should not be treated as current events.
Keep the outing easy
Ask about admission, the entrance, parking and accessibility when you call. Let each person choose one exhibit to spend time with rather than trying to read every label. For children, a short visit that holds their interest is more useful than stretching it to fill a whole afternoon.
If weather improves, investigate the nearby lighthouse. If it does not, keep the tower out of the plan and leave enough time for a comfortable return to the island.