Sleep lounge or hotel at CDG

If you have the resources, there are at least 4 hotels IN CDG. We would stay at one of the airport hotels. Back in our 20s, we would have camped out in the "lounge".

There are a bunch of hotels AT the airport -- we use the Novotel which lets us just hop on the CDG Val to get to the terminal in the morning. There are several budget hotels at Roissypole in addition to the Novotel, so see which one give you the best deal. There are over a dozen hotels inside the airport on the CDG VAL transport system

Closest hotels to Terminal 1 would be the Holiday Inn Express, Mercure, and Moxy. One stop on the CDGVAL. The CDGVAL runs 4 am to 1 am.

Here's a list of all the hotels at the airport itself, with a map showing locations.

When you return for "a full day in Paris," does that mean two nights there? If so, use booking.com to find a hotel in central Paris that meets your standards for cost, location, comfort, etc. People here will have suggestions and recommendations, but you'll have to supply a price range to get the most useful ones. If you are flying home from Paris the next morning, you might consider an airport hotel that night to avoid any possible morning delays.

Thank you everyone, appreciate your input!