Once we check into our hotel (Courtyard Marriott CDG), should we hop the shuttle back to the airport to get on the RER into Paris, or is there a better way?
Please share!

Most people in this forum thing the air buses are more convenient, safer (the US State Dept has issued a warning on the RER CDG trains about theft being rampant) and go to places more people want to go to than the train - if doing the train be sure to take the non-stop trains not the stopping locals which can get very crowded - about 2 of each each hour - slow one much slower. Free navette from Terminals to RER station.

If you're talking about just going into town for sightseeing, and you won't even have luggage, I think that is definitely the best thing to do (RER).

We spent a night at that Marriott two years ago.
Their shuttle took us to the airport in the morning.
The train station in there by the airport also, I believe because people on our shuttle trip were going to the train.
We thought their service was very good and often. I would go for it.

I did this in March due to being bumped by Air France. They put me in the Campanille Hotel which uses a shuttle bus to get to the airport. I believe it was across the street from a Courtyard.

I thought it ate a lot of time to take the shuttle. Wait 15 minutes at the hotel. 10 minutes to get to the RER station. Buy a ticket and wait for the next RER another 20 minutes blown. 20 minutes into Les Halles/ Chatelet. 15 minutes to walk where I wanted to be. The hurry up and wait seemed to never end.

The RER is about 8 euro each way, that's 16 euro. The ticket agent said I might as well buy a Paris Visite pass for 16.75 euro. All day transportation on the RER and Metro for zones 1 thru 5 which includes CDG airport. That's what I did.

The reason I mention all this is you said "we." That's more than 1. If there are 4 of you it would be faster, less hassle and about the same cost to take a taxi. If just 2 of you then you'll save about 1/2 using the RER.

I've stayed at the Courtyard Marriott several times, and like it very much. I've only stayed there when I've had a morning flight back to the US, and the shuttle works just fine for that. In addition to what Indytravel has just said, the Marriott's shuttle costs 5 euros roundtrip per person.

Now that you mention Sue4, I remember that the Campanile shuttle cost too. It's just that Air France comped it for me along with the hotel room.

At 7.75 Euros and no traffic to contend with, the RER is a great way to get into Paris if you're not dealing with a lot of baggage. Two airport hotels that are VERY convenient to the CDG1 RER stop are the Ibis and the Hilton CDG. I haven't used the former, but the Hilton is an extremely nice hotel and if you can get it for a decent rate, that may be your very best bet when you want to stay near the airport for an early flight. It's just a walk across the parking lot to the RER station from the Hilton and there is a complimentary shuttle to the hotel from the terminals. (I was able to pick up the Hilton CDG for 94 Euros/night last weekend off the Hilton website. That included breakfast, which made it an absolute steal.)