Air France shuttle bus from CDG to Gare Lyon

I have used both and both are fine. I didn't have trouble finding either.

The trains are more frequent but the bus is direct. If traffic is light and you don't have to wait around for the next bus it is probably quicker. If traffic is bad I'd expect the bus to be slower.

Cathy, easy cdg.com will help you with the Air France buses. Also parisbytrain.com is a good website for first time visitors. Hope you have fun.

Despite its name, Les Cars Air France is the bus service connecting CdG with Gare de Lyon. It stops right in front of the big train station. Your want route #4. Here is the link to the site http://www.lescarsairfrance.com/en/our-network/plan-line-4.html
You will note that you can buy your tickets on-line.
While it gives an estimate for the time of the drive, traffic can snarl the schedule, so making a tight connection to the train will be a gamble. Also if you have to buy a train ticket from an agent in the station you can expect to wait in line.
Bus is more comfortable than going by rail from the airport to the station, but also more expensive. This site provides a guide to the sprawling Gare de Lyon: www.parisbytrain.com

Thank you everyone for the great information. We are arriving at 6pm on a Wednesday, so we will probably hit some bad traffic. There is a group of 4 of us travelling together, so I'll see which way they'd like to go. I am opting for the comfortable bus from CDG to Gare Lyon, since our hotel is just a block from the train station and will be easy to find from the bus stop, which I found from Google Maps street view. I picked this location for our hotel, since we are leaving the next morning for Avignon from Gare Lyon.

Cathy,
I'm familiar with the Gare de Lyon, and the hotels around it, as well as taking the Air France bus from CDG. I know there is always the possibility of slow traffic, but I think sitting in a nice comfortable bus is preferable to taking the RER (which is likely to be crowded) -- and having to stand and change trains.
Go to the CDG website and look up Air France "Les Cars" as the bus is called, they have 3 different lines I believe, be sure you get on the one going to Gare de Lyon.

Good planning! Assuming you are settled in your hotel by 8 p.m., you may be ready for a meal and there are several places worth considering. Train Bleu in the station itself is renowned for its lavish decor but you pay for the surroundings as much as for pretty standard French fare, efficiently delivered. http://www.le-train-bleu.com/uk/index.php

An easy walk of a few blocks takes you to A la biche au bois, a real contrast. It is tiny and hectically busy with a fixed menu at 29 euros which is a real bargain considering the hearty cooking. The name translates, roughly, as White Deer so you can expect lots of meat. I've never found a webpage for reservations but you might ask the your hotel receptionist to telephone ahead. It's open until 11 p.m. 45 avenue Ledru-Rollin.
Here's a respected critic's review http://www.davidlebovitz.com/2010/10/a-la-biche-au-bois/