I have a flight connection with an 11 hour layover at CDG. The timing is good for a quick 1/2 day trip into Paris, so we are going to do it. I'm wondering what's the optimal method for getting from the airport to somewhere in central Paris, and then back to the airport again late that day. This will be on a Tuesday in March.
Our inbound flight (an overnight redeye from Seattle) arrives at CDG late morning (we're flying in business class on Air France, so I expect we will get some decent sleep and arrive in reasonably good shape). We're going to dump our bags, grab a shower at an arrival lounge, then head into the city (each with just a day pack with essentials for the day). I expect we will be ready to exit the airport and head for the city around 12:30 to 1:00 pm.
We need to be back at CDG to rejigger our belongings, check in, and clear security - I'd like to be back at the airport ready to knock out those tasks by 8:00 to 8:15, maybe 8:30 pm at the latest. Our onward flight departs CDG at 10:40 pm (our checked bags will be checked all the way through so we won't have to deal with them, but we will recover our carry-ons from a left-luggage facility).
I'm looking at "Le Bus Direct" which seems to be a good option. They appear to leave frequently (every 15 minutes), trip time about 1 hour, not expensive (31 Euro round-trip). We would have about 5 hours in the city (afternoon to early evening), which seems doable - enough to get a taste. We've been before, several times, so we have no "must-see" list, just want to enjoy walking around, enjoy the sights and smells, grab a bite for light dinner, take a few photos. Probably around the Eiffel Tower, Arc 'd Triumph, Louvre, Notre Dame neighborhood (I know the cathedral is under reconstruction). Lots of walking is OK, we will be between two long flights.
Does Le Bus seem like a good choice for us? Is it best to buy tickets in advance, or just buy when we are ready to catch the next one - do they sell out? If there's a chance that return bus trips may sell out I'd like to be secure in having a reserved seat that gets us back in time. Is the bus schedule reliable and consistent?
Any other tips/suggestions/reality-checks welcomed. Thank you!