Hotel Armoni, a small boutique hotel, was a godsend. They arranged transportation from the airport. I showed up at their door at 10 am after an all-night flight, and they fed me breakfast while they readied a room for me right away. I was expecting to leave my luggage and walk around until check-in time, but instead was able to take a shower and a quick nap before going out to exlore. The hotel is just off Porte de Camperret Metro. Right next door was a lovely little restaurant, Champotes, which apparently had just opened and had a wonderful chef and great food and service.
There was apparently some construction going on on the train route from Paris to Chartres, where my tour began, and the detour involved three separate trains and 3.5 hours. Rick Steves suggested a car and driver for a price of 320 Euros. I found Team Daytrip for half that price, and they sent me the driver's name, phone number, picture, and license plate ahead of time.