Thanks Andrew. I wouldn't even think of winging it. Directions are on the hotel website and I know how to access the maps. I just meant in general...lived in Le Perreux for several months and used to get around Paris without a second thought.

When I arrive in Europe after an overnight flight, I'm tired for sure, but the excitement of being there is sufficient to get from the airport to my hotel. Study the instructions for the RER, try to get some sleep on the flight, and have a map handy so you can navigate from the Saint Michel RER stop to the hotel.

If you'll be returning to CDG via the RER for your flight home, I would buy your return ticket at the same time you buy your ticket for your inbound trip. You can also buy whatever tickets/passes you'll need for the Metro at the same time. I usually just buy a carnet (10 tix), but I don't rely very heavily on public transportation in Paris, as I like to walk.

I hope you like the hotel. We found it comfortable and clean. For the price and location, it was a good choice for us.

It's just a private car, that's all, and that is the going rate nowadays for those. Taxi fares depend on day, time of day, and traffic, so it is possible that is not really a whole lot more than a taxi fare would be. I can't imagine it is less, though, so am not sure the purpose of it vs. a taxi.

Given that location, I'd take the RER, though, if you really understand you are going to have to walk several blocks to that hotel, at a slight uphill. I wouldn't take the RER if I had a lot of (big) baggage.