It's a big, fascinating park with things to do in several places. Near Florida City, the Anhinga Trail is a must. Gators galore and birds everywhere. While you're in the area, stop to buy fruit and more at "Robert is Here."
Up on 41, take the narrated tram (or bike) into Shark Valley. Worth booking tram tickets in advance. Parking there is tight.
Then there's the tip of Florida...Flamingo Campground operated by the NPS now takes reservations and has electrical hookups in many sites...also tent sites down on Florida Bay. The area is one of the only places in the world you'll ever see crocs and gators living in the same place.
A real highlight down there was an inexpensive guided boat tour up Buttonwood Canal into the back waters of Whitewater Bay - leaves from the marina/boat launch near the visitor center where you can rent kayaks. We also enjoyed ranger Croc Talks and walking around the Eco Pond to see the Roseate Spoonbills and many other birds.
Over near the northwest side of the glades, there's a good state park (outside the NP) with hookups called Collier Seminole.