In Crans-Montana, the local innkeepers have put together a laundry service.  They'll give you a small trashcan-sized bag, and they'll wash anything you can put in it for about $20.  You give them the bag and the cash, and it will come back to you freshly laundered.  

While expensive, this is a wonderful service they offer.  It allows some latitude in how much to pack, knowing you can re-wear stuff after that.  

The laundry service certainly isn't required, but it is awfully convenient, and right in the middle of the tour.

The following is an excerpt provided by the Tennessee Ambassadors of Music director:

Some people choose to take enough clothes for the full tour.  Others will take less and wash out what they need in the bathroom sink and hang to dry over the bathtub. You can actually buy a clothesline designed for use traveling - no pins needed. Like this one: LINK  Just hang over the tub, not the floor, so nothing drips on carpets or floors.  This is one option and several of our travelers through the years have done this. Some hotels frown on washing clothes in the sink - others actually ask you not to do it.