Okay, we're doing this. Staying north of the city seems impossible so we'll hang a St. Christopher medal and drive to Marina Port de Plaisance. I just booked tickets for the Paul Simon concert, June 13. The river shuttle does not seem to operate on weekdays until late June but I see the Metro yellow line goes to nearby Universite de Sherbrooke. The Marina calls their service RV stopover and says no reservations but I expect we'll be alright mid-week that early in the season. Hoping they allow multiple days. (Last time there was on our sailboat in 1995! Did not foresee returning by RV all these years later.)
Thank you for the replies, especially JackD. Always good to find someone right there.
Happy travels to all!