I'd recommend a travel cage or a bonding pouch. When I picked up mine it got a bit late on the way home and one came out of the pouch and ran laps around the car. As cute as that was it's not that safe so I wouldn't really recommend that, distracted driving can be pretty dangerous and the little guys might get lost or squished between luggage, plus it could be a pain to try to catch them if they don't want to come back. Mine have done a few trips in the pouch already and were fine.
I wouldn't worry too much about bumps from the road, as long as you don't get into an accident or something like that they'll probably be okay. They live in trees in the wild and have to deal with occassional swaying from the wind, so a swinging pouch probably wouldn't be too detrimental for them. Give them something to nibble with moisture in it so they stay hydrated and they'll probably do fine.