How can I get from CDG to downtown Paris via suburban train (RER B) during a period of labor unrest?

You can take the Roissybus from CDG to Opera if the RER B is not running.

50% of RER B trains are running. During peak periods, I would guess that means that you will have to wait about 20-30 minutes on the platform for the Paris-bound RER B trains. The RER B will stop at Chatelet Les Halles. I think you are getting weird machine translation results with "to the limits of the RATP zone." The bus service appears to be working better. Try the Air France Bus: http://www.aeroportsdeparis.fr/ADP/en-GB/Passagers/Access-maps-car-parks/Paris-CDG/Access/public-transport/paris-cdg-car-air-france.htm Personally, I wouldn't worry about the strikes and fuel shortages. You will be in no harm. You will just have to be patient.

The best solution is to do booking with taxi company or  driver or in Advance . In normal time commute works as follow : There are few choice of transportations for   CDG - Paris  : Trains ( RER) and Bus services are available between center of Paris and CDG airport as well as Orly Airport . RER train has only one station in CDG Terminal 2 , so in any  terminal your arrival ( or departure  ) is , you will need to go to the train station , and  CDG  is big . Ticket to paris cost about 10 euros and take at least 35 Min to arrive to center of city . The interval of trains is 3-4 train /hour . There are few major inconveniences with RER ; first , if you have your family and luggages with you, carrying all that through airport and in side of crowded train and stairs, can be difficult. second;  the train passes through some not very safe suburbs of paris and you really have watch your belongs and wallet etc . Bus – there are two major bus lanes between CDG and paris , First is the normal City bus, and  ticket cost 11 euros , it is usually crowded and seldom you may find place to seat . Trip time from CDG  to paris is 1 hr. The second bus lane is Air France Bus, in this one you will have individual seat and is quite similar to American « Greyhound Bus » . The ticket of this lane is 17 - 21 euros and trajet time to Paris center is 75 min . Shuttles – the shuttles are the least good choice ! They take several people (up to 8) from different terminals and drop them off in different locations in city , it is very time consuming and if you are more than one person , taking normal taxi will cost about the same for you , beside taxi is much faster and more convenient . Taxi -If you prefer to have more comfort and privacy you can take a normal Taxi ; During the night or early morning taking a Taxi is recommended, rather than trains !    These examples are based on parisian taxis  basic rate, fares can vary  according to the difference of rates in day and night , weekdays and holidays, time of day and  traffic conditions.          From   CDG - Charles de Gaulle  airport-  to center of Paris costs about 50 euros. Can take  from 45 min to 70 min depends to rush hour traffic. in heavier traffic it will cost  up to 65 euros . From CDG to Orly airport cost  60 euros , and takes about 55 minute .  From Orly airport to center of Paris costs about 30 euros . Can take from 35 min to 1 hr according to time of day and traffic.  From center of Paris to Disneyland costs about 55 euros . Takes in average about 50 min time . From CDG to Disneyland cost about 55 euros .  takes about 45 min.  From center of Paris to Versailles palace costs about  35 euros. Takes in average about 35 min . Average taxi ride within the city of paris costs between 10 - 15 euros. For more informatins visit : http://www.paristaxi1.com/

When on strike, the CDG-gare du nord line will always work, at least one train every thirty minutes. You will have to get down in gare du nord and switch trains; just go two stories down and you'll find yourself on the right http://dock.to reach Chatelet from gare du nord, you can either pick b or d rer lines, just one stop for each, and there's also the subway.