Hello GrayRaver,
Up to now, only one charter provides service from the end town to the beginning town on Friday; Pork Belly Ventures.
By using them, I’m at the start town late afternoon on Friday and get the experience of watching the “circus” come to town.
It also provides a nights rest prior to arrival day allowing you a relaxed experience of several things that others miss: the incoming hoard, the expo, an opportunity to ride to the Missouri River to tire-dip before Day One and a good nights sleep before the ride starts.
The Friday Eve / Saturday AM experience is one of my favorite parts of the ride.

All the best, D