Plenty of riding out of Jackson...If he wants to book a guided powder trip there are multiple companies.. I would suggest Scenic safaris or Togwotee...i know guides at both and could recommend a specific guide for a good powder trip. He can also rent sleds if they don't want to go guided and pull a trailer wherever they want to ride. . One thing about going guided that time of year, is to book SOON because it is busy as hell and normally the trips book up in advance