On my way from CDG ( at around 8 PM ) to Gare de Lyon I wil need to change over from the RER B to the RER A or the RER D at Chatelet Les Halles ,to get to Gare de Lyon. From what I have heard the Chatelet Les Halles is enormous . How difficult will the switch over be ? I will be jet lagged with some luggage.
Thanks for the advice in advance.