Stephen, this was our second RS tour, in 2015. We loved every minute of it. It was fast paced, but not overwhelmingly active or tiring. The bus rides are not too long. Do take and use your guidebook to help orient yourselves and to plan your free time. The basic language skills (Bonjour, merci, etc.) were very helpful during the trip as we were encouraged to interact with locals everywhere. We took the RER from the airport, but I would take a taxi to make it easier. CDG was as bad as its reputation.
One thing we agreed on was that it only gives an introduction to Paris. You dont spend nearly enough time there, and the tour doesn't include some of the things you might consider important like Versailles or the Eiffel Tower. So my suggestions would be to plan on a few extra days before or after, or both to enjoy more of Paris. I think after would be better, as you'll feel confident and experienced.