If you'd like to add some extra culture to your trip, put Museu do Cárcere on your must-visit list. Check for guided tours or just roam around at your own speed.
You'll be spoiled for sightseeing choice when staying in Angra dos Reis. Museu do Cárcere is an ideal place to kick off here, but there are lots of other interesting spots to visit. Lopes Mendes Beach, Abraão Beach, and Abraãozinho Beach are close to the museum and and will cap off your day nicely.