I walked the entire walk; my wife just did the easier parts. Both of us enjoyed it immensely. The north end from Memorial Blvd. to Narragansett Ave. is very easy, suitable for someone in a wheelchair. The area near the other end from Rough Point to The Waves is fairly strenuous, not recommended for anyone with virtually any mobility issues. That said, I am a healthy 73-year-old and had no difficulties.
There are less views of the Newport Mansions than I might have liked but great views of the coast. And there are some very nice mansion views.
We parked on Narragansett Ave. at 40-steps; parking is $2/hr. On the other hand, parking at the south end is very difficult to find and not close to the Cliff Walk.