I am arriving at CDG II Terminal 2A in two days with my 16 year old daughter and need to know how to reach the RER B stop. Will I be able to walk or do I have to take a shuttle?

Additionally, I am flying from CDG to Nice via Easyjet next week and will be taking the RER B from Luxembourg to Terminal 2B. How much time would I need to ensure that I arrive at the gate by 08:20? Do I return to the same stop as above and then shuttle or walk to 2B?

Thanks in advance,