Whitewater trip in the Yukon territory: someone to join us?

We are planning a whitewater trip in the Yukon territory with our packrafts. We thought about Snake, Wind, White or Hyland River. We are experienced in outdoor adventures and can manage whitewater up to class III.
As flights and shuttles are very expensive for two people, we had the idea that someone might join us – could be only for the transportation, could be for the hole trip. We have one campervan (for shuttle). We would start in July, but we are quiet flexible.