Ten people could easily fit into two sedans, but not with all their packs. I can put all the tents and perishable food into my trunk, and we could load all the non-perishable food into the other, but then, where do we carry ten backpacks, sleeping bags, etc.? I have a clamshell that could go on top of my car, but I have my doubts as to how much I could cram into it.
Plus, ten people in two sedans for 1700 miles is not very comfy. Far better if we can nab a min-van to go with my Breeze (which is being serviced for the summer as I type this).
Gas is also a consideration. My original budget estimated $3.25 per gallon, I think. Being a trek budget done by yours truly (who almost always brings home budgeted but unspent group funds), I'm willing to see if we can make it without charging people more. The Crew could probably absorb a bit of an overage, too. But if we have to take three vehicles, all bets are off, and we'll have to confabulate about this.
Still, we're making progress.