I was hoping to get some advice from Paris experts in this forum.
I have rented an apartment near Rue du Bac metro station. My wife and I travel light - usually with 2 carryon suitcases and a camera backpack.
I am researching my options for CDG transfer. Closest RER station is St. Michel and the closest Air France Bus stop is Gare Montparnasse. I don't find an easy metro transfer from St. Michel to Rue du Bac but find a direct line from Gare Montparnasse to Rue du Bac. Am I correct in my analysis of the options? Are taxis available at either station? Any other recommendations?

I'd go with the Air France bus, and yes taxis are available at the stations. Just look for the taxi stand.

Taking the RER would involve two transfers, a "drag" with luggage.

Taxis are available at all the stations, but once you add the taxi fare to the AF fares for the two of you, for a few euros more you could just take a taxi directly to the apartment from CDG, which is what I would recommend. Though, there's a considerable discount for round trip AF coach.

If you want to economize, you could take the AF coach to Montparnasse, then a bus to rue de Bac.

Try the RATP trip planner, in English. I did; you can take the RER from CDG to the Saint-Michel Notre-Dame station, then take the #63 bus (direction: PORTE DE LA MUETTE) to Rue du Bac. If you have an exact address for your apartment, you can punch it in here with a departure time/day as well:

http://www.ratp.fr

(and follow the links to the trip planner.)

RER are frequently on strike - I'd go with Air France bus and take a taxi for the rest of the journey.

The AF bus is going to cost you 30 Euro for 2 then a taxi from the stop to your hotel is probably around 10 euro, you can get a taxi directly to the hotel from the airport for about 10 euro more and no schlepping luggage

I am surprised at the low estimates for the taxi cost. I will be traveling on a Monday around 9:30 AM (rush hour?). Will this effect the cost of the taxi?

........ and the Roissybus (9.10 Euro) which departs from all three terminals at CDG will drop you off at Palais Garnier just across the River Seine where you can taxi from there. About 1 km difference than taking taxi from Gare Montparnasse. A Bus 68 stop is right on Rue Scribe where Roissybus terminates and will drop you off right at intersection of Rue du Bac and Boulevard Saint Germain. This is another way but as djkbooks has suggested, taxi is the easiest if you want to spend the 45 - 50 Euro.

Would that be 40 to 50euro for 4 people or would it be more? Sorry to hijack this thread!

It would be a bit more for 4 as there is a charge or 1 euro per bag and I believe it's 2.75 per person after the 3rd.

Also bear in mind you'll need a minivan taxi. There are lots of them so just wait for one to pull up in the line at CDG.

An update about the Velib system. I used my American Express Blue card to sign up for the system with no problems. I have used it now for the past 3 days. It is a great system for locals and tourists alike.

Sorry everyone. Added the info to the wrong thread.

I ain't ridin' no Velib from the airport. No way.

We took the RER from CDG to Saint-Michel Notre Dame a week ago tonight. You have no idea how confused we became trying to get from the RER to the Metro to go to Invalides. I've used the Metro in Paris without difficulty on at least seven trips but never encountered anything as confusing as trying to get from the RER to the Metro. The little map thingie we were given when we bought our tickets at CDG was useless, as were the signs down there. We relied on the friendliness of several Parisians along the way, who were themselves admittedly also flummoxed. I feel fortunate to have survived to be typing this. Please do yourself a favor and take the AF bus! BTW, we were not lugging luggage.

The Roissybus is more like a city bus with racks throughout for your luggage. The one time I took it, it was very crowded and I had to stand up. Les Cars de Air France are more like tour buses—roomy with plush seats and head rests—and the driver takes your bags and stores them in a compartment under the bus. It's definitely worth the extra €6.10. That being said, we always take a taxi; as a percentage of the cost of the trip, it's a mere bagatelle.

Unless syou are on a very tight budget, just take a taxi from CDG to your apartment. After many arrivals and trials of multiple options, it is the best option in terms of ease and convenience - not to be minimized when considering you are just arriving after an overnight flight. If I am solo with little luggage the RER is a viable option, but for two or more the few extra euro for a taxi = good value for money.

I took a taxi my first time based on advice on boards like this. Won't do it again.

Sorry, but I sat in traffic for an HOUR.... you don't want to know what it cost

I know take the RER, but I am pretty familiar with both Paris and the train/metro.

Otherwise I would take the bus and then a cab.

I avoid RER . We often take Roissybus ( we travel with carry ons ) and taxi or Metro ( if there are no transfers) further.
AF bus is also an option ( depending on the location) and the number of people traveling ( i.e.cost)

I have also taken a taxi but only on Sundays. One can get stuck in traffic $$$$$ .
Another option is RER to St.Michele and taxi to your apt.
Your original plan: bus to Montparnasse and Metro to RduB would work just fine and probably cost the least..

Hi, IMHO a lot of this is to do with where you are staying. on our most recent visit about 2 months ago, we were going to be using the RER not only to get to and from the airport, but also to get to the stade de france. therefore I looked for a hotel within walknig distance of an RER station, which worked out fine, despite the long queue at the RER station at CDG when we got there [20 mins to buy tickets from the automated machines; I've no idea how long it took at the manned one].

However, if I were staying where you are, I think I'd go for the bus and cab option. whatever you do will involve some waiting though.

It was either a nightmare or a horrible memory: lugging a suitcase up several thousand stairs at the metro/RER station at St. Michel. Actually it was two suitcases along with a five year old. Never again. Take a taxi.