Seeking advice regarding Air France Coach...We (2 of us) will be staying at a hotel within 800 meters walk of Montparnasse Station. Arriving at Orly Airport 11:30 on a Tuesday in May and departing from CDG airport at 13:30 on following Saturday. We Plan to take the Air France Coach to and from the airports via Montparnasse station. Will we have to switch to a different coach along these routes, or just board and go to destination? How often does the coach depart Montparnasse to CDG and approx. how long is the trip to CDG? We want to arrive at airport by 11:30AM on Sat.(2 hours before flight)...so what time should we arrive at Montparnasse to catch coach. Would we be wise to buy tickets in advance to ensure seat or is it first come first served? Any advice greatly appreciated. Thank you!