Power shouldn't be a problem. They ran (in later years) D&RGW SD40-2Ts, GP40-2s, GP40s, and in earlier years, FTs and F7s and PAs. Their steam generator car was an Alco PB. Steam engines used included mallets, 2-8-0s, 4-8-4s and 2-8-2s. I'm sure other types were used. Passenger cars look like 2 eras also - the later smooth sides in orange & silver as well as the early heavyweights in pullman green (some of which were lettered "SKI-TRAIN"). After the SP/DRGW merger Southern Pacific power was used too.
Did you check Walthers for their D&RGW passenger cars?