Just a thought - you might want to weigh the cost of shipping the cories versus simply buying new ones when you get up there. Add in the risk of shipping, and the possible store credit, or even cash.
As for the betta, as I know that people get attached to them, they can survive for long periods in ridiculously small containers. Think about a huge jar with a lid that you open at rest stops and overnights. Or even a 5g bucket belted in to the passenger seat
