When my son Matt wanted me to haul his bike club from A to B, I screwed some old square metal deck railing onto the wooden bed of my car trailer like a bike rack, giving me the option to haul 10 bicycles....and 11 of us in the truck and camper! Five of us were in the truck's cab (luckily some of these folks were pretty small) and Six were IN the camper laying on the bed or seated around the dinette. I would not want to go to New York this way, but for a short ride it could be an option.
The bikes were all mountain bikes and I was the shuttle for a Trans-Sierra Trek. They rode for 15 hours to get from Truckee to Nevada City over several high passes on all dirt.
Failing that, just buy a big, old, good condition, gross polluter with a big engine that seats 7. A 1991 Sub would be fine. Or an older Jeep full-size, 3-seat Wagoneer. People are dying to get rid of these. Just what you can use.
jefe