Thanks everyone for your suggestions.
I contacted Southeast Tours and they informed me for our own transportation, the cost would be $25.00 less than if they provided the transportation. ($125.00 per person rather than $150.00 pp) They did suggest leaving the driving up to them, but we really want to explore the mileposts of the Klondike hwy.
Did Orca Enterprises give you any discounts for booking two tours? And does your Yukon trip include horseback riding around Emerald Lake?