Middle Prong Trailhead is at the end of Upper Tremont Road, which is unpaved but maintained. A parking tag is required if you park longer than 15 minutes, and pets aren't allowed on this trail. The nearest listed restroom is at Great Smokies Welcome Center in Townsend.
The first 1.3 miles of Middle Prong Trail has an accessibility assessment; free GRIT Freedom Chairs are available first-come, first-served for that section. The cascades approach falls within it. Check the assessment details and chair availability before you go.