One option you may want to look at for the D&S is the Silver Vista. The age limit on that car is 16 and up, and you can still order drinks from the car attendant. Just like you would in the Alamosa, Cinco, or Nomad.
As far as I'm concerned, the Vista is one of the best cars on the railroad. During good weather, of course. If you don't want to risk running into bad weather, the San Juan would be my next choice. It has the same seating arrangement as the Vista, but is enclosed. However, there is no attendant in this car, so for drinks and the like you would need to make your way to the concession car.
Just a thought.
-Jon
D&SNG