1975 20ft. Argosy appliances

We have the Little Bug all striped on the inside and all old appliance removed, still have a lot to do before rebuilding but would like some advice on replacing the furnaces and refrigerator. The old furnaces is the nt-16 and old refrigerator is the rm-46. The best I have seen would be the RM-2451 for the refrig. and NT-16seq. for the furnace. Does this sound about right for a 20 foot trailer.? Has anyone condensed the large vent to a smaller one coming off the cabinet from the refrigerator.?

thanks for any advice.