Shark Valley has nothing to do with sharks but lots to do with the wonderful Everglades. This tram tour which is privately run at Everglades National Park- Shark Valley is a very informative and fun way to see this important area of Everglades Park. You will sit in a covered open tram and comfortable see all the gators and birds. There is a fine explanation of the ecology.
If you want exercise then you can rent a bike and ride yourself around the same trail. You will be up close and personal with the gators. Get to the tram ride about one hour early, it does get crowded.