The comfort station is probably similar to all other comfort stations at WDW. Very clean and comfortable.
The area is basically a large, grassy field with fire pits scattered throughout and some trees and picnic tables scattered about.
Not sure about how many cars allowed per group. There is a decent size parking area there. The buses do come by pretty regularly. There is also a quick walk over to the Meadows area.
Since you already have reservations, then you know it is $10 per person per night which isn't too bad. Not sure about electrical hookups if any.