Roosevelt Campobello International Park
This park is on Campobello Island, New Brunswick, Canada and can be accessed via the FDR Memorial Bridge at Lubec, Maine. In the summer you used to be able to get there by car ferry from L’Etete or St. Andrews, New Brunswick or Eastport, Maine (via Deer Island). The ferry is currently (2018) not available. This is a good place for birding – it is on the Atlantic Flyway – and wildflowers on the many drives and trails. Habitats include fields, marsh, sphagnum bogs, ponds, cobble beaches, and coniferous, deciduous and mixed forest.
Phones for the park are (506)-752-2922 or the toll-free 1-877-851-6663.
Here is their website and page on accessibility.
There are numerous trails and drives including the wheelchair accessible 0.3 mile Eagle Hill Bog boardwalk and the “flat and easy” Lower Duck Pond to Raccoon Beach trail. A few others sound pretty easy too. Call first.