Has anyone taken this group tour? It seems great, except they can cancel at the last minute if they don't have the required minimum of 8 people. Plus, tried signing up with them..they confirmed, then I received an odd email as if it was cancelled. I've tried emailing them a couple of times trying to figure out what was wrong, and haven't received a reply yet. We don't go until Sept. 2015.
Why don't you just phone the RS office in Washington State?
Are you saying that this tour is organised by the Rick Steves group? Or does RS stand for something else? Is Mondo somebody who actually delivers the tour? (Mondo means world)
Mondo Tours is a company based around Naples. The details of the shared tour option that they are promoting to Rick's readers are in the Italy guidebook. For feedback from a few Travel Forum users who took the tour, see
https://community.ricksteves.com/travel-forum/day-tours/mondo-shared-tours and
https://community.ricksteves.com/travel-forum/italy/mondoguides-it.