This day was devoted to the Everglades National Park. We first entered from the Everglades city side to take a boat tour around ten thousand islands. It cost ~$37 for 1.5 h. During that tour, you can see different birds and dolphins. Views are mostly the same, it’s just a nice relaxing ride.
After that, we entered the park from the Homestead side. We went to the Anhinga trail (gators and birds) and then made several stops on the way to the Flamingo area. Most of the time we were fighting with mosquitoes. At the end, we gave up our last walk because of them.
Ask for a map in the visitor center. All national parks have great maps with all points of interest highlighted. Depending on the time available visitor center employees can advise you what to see and do. Also, you can find all the details about this national park on their website (including any weather and roads status alerts): http://www.nps.gov/ever/index.htm
We also stayed overnight in Homestead to go to Key West next morning. Homestead is a middle point between Biscayne National Park and Everglades National Park. It is primarily an agricultural area.