Thanks for the detailed additions!! Very helpful and much appreciated. Just a couple quick questions:

1. Is it looked down upon by the hotel and/or bus drivers if you take the CDG shuttle to Hyatt CDG and then transfer to the free Hyatt CDG shuttle to Paris and then walk to the Vendome? Or do they even know? I actually am arriving into CDG around 8AM so this option might work best for me (plus I'd get the opportunity to check out the Hyatt CDG which I've never seen and wouldn't see otherwise).

2. Sorry, this might be a stupid question, but....................Are the RER trains similar to the London Underground/"Tube"? Do they have day passes so I can buy a day pass and travel all around Paris that day? We arrive in the morning and basically we'll be sightseeing all that day. If I need to buy a RER pass anyways for that, I might as well take that from the airport also if I'm already paying for a daypass that day, right?