We plan to book a room in either the 6th or 7th Arrondissement. Looking at map, it appears that we would be best departing from Orly Airport?
Also, if Flight Guru site legitimate for booking flights?
Can´t help you on booking flights but for an early morning flight from ORY, the Left Bank is no more than a 20 minute, 32€ taxi ride away. If the alternative is CDG, I always prefer ORY.
Orly is more convenient, but if flying out of Orly means that you lose the benefit of a non-stop flight or have to spend more than a few dollars extra, it is not worth it.