The overnight stay changes the whole picture. I would almost never stay at a CDG hotel unless I were flying out early the next day. There's nothing out there, the hotels and food are not cheap, and you spend time and money going back and forth instead of seeing and enjoying Paris. A real waste on all counts.

I would go into Paris with your luggage. If the RER is not your thing, take an AF bus or the Roissybus, get a hotel near your chosen stop, stash you luggage, shop, eat, have a great Saturday and Saturday night and Sunday in Paris.

Have the hotel order a timed cab for you to get to Gare du Nord for your train. Gare du Nord is not a bad security risk, just don't talk to strangers and keep an eye on your belongings.