Rer A

The Rer A terminus (ending lines) are:
Saint-Germain-en-Laye - Poissy - Cergy-le Haut - Boissy-St-Léger - Marne-la-Vallée- Chessy.
However there are other terminus on those lines, a train can go from one station to another of those lines without reaching those terminus.

Here is a map of the Rer A, you may also check the Paris rer map.





If you use a ticket t+, you can only travel between Charles de Gaulle-Etoile et Nation, beyond you need another pass.
The rer A has only one station in the zone 2 (Vincennes Station), You can't use your ticket t+.

The frequency of the Paris train depends on the branch, on the hour of the day, the day of the week, the period of the year, the type of day (normal day or public holiday)...

In rush hours and for the common section, the frequency can reach 2 minutes from east to west, and around 2.5 minutes in the other way. 
The rer A frequency can reach 20 minutes on the week-end and holidays, or even 30 minutes for off peak-hours, depending on the branch.