100 miles packed with attractions.
The overseas highway, which takes you over the Keys can be driven in about 2 hours. However, if you take your time you will find there is lots to see along the way, and explore. There is the Wild Bird Sanctuary on Marathon Key. Self guided tours will take you past all the averies where injured birds are treated. If you walk all the way through the sanctuary, it will take you to the northern side of the Key, where an abundance of birdlife usually gathers. Entry is by donation.
On Pine Key and No Name Key you have the opportunity to see the smallest of all deer species, the highly endangered Key Deer. Speeds are slow for their preservation, and also to actually get to see them. They are very shy.
There are also many places where you can still see the damage from Hurrican Wilma, more than a decade ago. This damage is also clear in the Everglades NP where the buildings and mangroves have still not recovered.
I am sure your specific interests will find many more places to explore.
Florida has an excellent free State map which shows all the State's attractions. Well worth getting from the tourism authorities.
Lifey