I was on this tour in August and I was thoroughly impressed by how our tour guide, Consequence, involved the whole tour group and made it fun and personal for everyone. She has a great talent for storytelling that strikes a nice balance between the macabre and light-hearted quips.
Lots of photo ops for the folks loving on the 'orbs' (the kids on the tour seemed to especially like this), and great stories for everyone. Lots of really great historical info along with the spooky storytelling--Pirates, ghosts, murder, intrigue--this tour packs it in!
The walk is easy, but watch out for the uneven footing--although I suppose that's the "charm" of Newport sidewalks. Maybe, as other posters have recommended, consider bringing a flashlight. :)
I highly recommend this tour if ever you're in Newport!