Well, on a trip some years ago, we ran our own.
Takes a lot of co ordination between the trip members.
Rig and launch rafts the evening before official launch day. I do not know if this is allowed now, but at the time, we launched at the ramp then took the rafts down to the bank across from our camp site.
Got up early the next morning and the drivers left ASAP. Rest of us finished loading and waited. It takes a while to go down and back and one of our drivers brought the other drivers back. Again, the trip has to have the vehicles and trailers there to handle things with one less vehicle.
Bottom line, doing the shuttle your self is a real pain but it can be done or at least we did it. I do not know if the Rangers now will let you launch late afternoon and tie down at the river bank there at camp. I would for sure check as the rules have changed quite a bit over the years.