I would suggest that they plan out their long-distance travel from major city to major city. Buy the tickets (air or rail) early to get the best prices. Then they can take day trips from the major cities. If they are using airbnb then they probably don’t need to book rooms too far in advance.
I just want to wish them Bon Voyage!! No matter what they decide or fail to decide, I hope they have a great time and lots of experiences to remember their entire lives!
Not a college trip…but after the Peace Corps…DD travelled with two,friends for six weeks. They were departing from Africa…and travelled east, going to Capetown first, then Singapore, Malyasia, Indonesia, and Sidney. They also had a 36 hour stop over in Istanbul. For them, it was all about the money. Shoestring budget. They started planning about three months before they departed. All done online.