I would go with either Big Thunder Mountain or Space Mountain. Both are tamer than Rock n Roller Coaster or Expedition Everest. Also, Everest's drop and RnR's launch can be a bit intimidating before getting on the ride to entry-level coaster enthusiasts. Other than that, it's just a factor of how much riding a coaster in the dark bothers the person. Between the two, I would slightly favor BTM just because you can see exactly what's going on and where you're going.