- clear passport control
- hop on the ADP airport shuttle #5 to "Terminal 3/Roissypole"
- the bus stops in front of the IBIS hotel at Roissypole where you can get a room at 10 euros per hour between 10am and 6pm (note: there are several Ibis at CDG; look for "Ibis Paris Charles de Gaulle Aéroport-Gares").

If you can skip the transfer desk and have a short wait at passport control you should be able to get to the hotel within 30 minutes of arrival. This will give you a good hour to use the room before you head back to your boarding gate. The shuttles run every 7 minutes and the trip is usually quick. There are also some spots to pick up coffee, etc. in the lobby or just inside the train/bus terminal.