Changes

Take the RER Line A (Red) in direction Boissy St Legere until the station Nogent Sur Marne (~ 2€). There, leave the station in direction Rue "Joinville" and follow the sign to the A4. Its about 30 minutes by foot. If someone stops ask if they can take you at least to the next gas station, there is no toll (péage) to get there so it's likely you will get at least to there.

Porte d'Orleans, at the ''périferique'' seems okay, Metro Porte d'Orleans. There's a gas station, and a good spot at the traffic junction to the "périferique extérieur". Don't go with cars going into the suburbs. The next tollway or gas station takes about 50 km!