We flew Air France from Boston to Paris (9:30pm departure) 3 weeks ago. You leave out of terminal E. You will likely come in to Terminal B or C. It's a bit of a hike between terminals, but you do all of the walking inside security. I often walk back and forth between terminals to get some steps before boarding the flight. Remember you can always ask for assistance through the airport, by asking your airline 2 days before the flight.
If you'll have access to Air France lounge it's at the end of teminal E, closest to the beginning of terminal C. If you've booked this as a single flight (delta code share's with Air France) then likely they will look at your passport before leaving Austin (at the checkin desk), but if you're not sure just go to the desk at the departure gate in Boston, and ask them if they need to check your passport. Often you'll hear several names announced to proceed to the departure gate desk for passport check. If you get there before they announce, they will just check right then for you and you'll be all set.
For our flight we sat in economy, the food and service was standard airline fare. They did offer wine before and during meal service, but always ask for a glass of water with it, stay hydrated! We have priority pass which used to allow us into Air France lounge, this time I noticed they have a new time restriction, priority pass holders only allowed in the mornings until 1:30pm. The woman at the lounge desk allowed us in because we were flying Air France. The lounge is fine, nothing too special but it's nice to get some food and drink before boarding the plane, then I can try to skip the meal.
