The Huckleberry RR. coaches were empty shells when they were received and required extensive rebuilding. In a sense they are historic, as the original car bodies were built as early as 1882, but the interiors were long gone, as were the trucks. In the case of the C&S coach, it has an intact, period interior and fittings. Using it in daily service would be a crime.
When you have an intact artifact, you preserve it. Since the loop trip is relatively short, converted box cars or gondolas should serve well. Save the historic stuff for a museum or for (very) occasional special use. Unfortunately, the CHS seems to be rushing into this in a completely half a--ed manner and the result may well be the effective loss of several historic pieces of equipment. And they call themselves an "Historical Society!"