St. Augustine Alligator Farm Zoological Park
The St. Augustine Alligator Farm has every living species of crocodilian. In addition they have a wide range of other animals from around the world. Not exactly a contemplative nature walk, but it looks like fun. Here is a description of the birds there from Florida Birding Trail. Great place for photography.
Here are some rave reviews from from Trip Advisor and others. This is their website. Map Phone 904-824-3337
The whole park is wheelchair accessible. Children and adults in wheelchairs are half price and seniors, AAA and military get a 10% discount.
This shot of their boardwalk is thanks to photographers Gordon and Cathy Illg.