My lucky duck son (age 21) is heading abroad for a program this summer, and at the end of it he's taking 2 weeks to see the sights in Europe on my own! He's been twice with high school trips but they were whirlwind, and this time he can plan his own. Our Viennese friends are leaving for vacation the day he starts, they go to Croatia which DS was thinking of seeing anyway. Of course, they didn't say " hey, kid, why not join us for a day or two?", so not sure what to do there.
Anyway, it's been a long time since I was a college student doing the youth hostel thing, and I wonder if anyone has tips on the current youth hostel environment, cool ones to stay and or ones to avoid? He's starting from Frankfurt and heading to points south, I think, then ending in Vienna. He'd love to hit the Adriatic coast!