Lemon-jar helped with some ideas!
Vriska’s a sk8rgiiiiiiiirl, enjoying extreme sports and sometimes going out to board across town so she can avoid her mother. Takes a lot of chances, and she knows a lot of shortcuts in her area. Maybe in Portland, Oregon, since that is apparently a Skateboard Capital? I don’t know much about this stuff.
Aradia? She’s up in South America, in the Andes. Her parents are studying the Incas and their empire, and she likes to climb quite a lot.
Terezi… Well, bicycles are about balance, so maybe that? Cue the jokes of what she is in this universe. It’s also a possible extreme sport, if one wants her to come at odds with Vriska. I know it’s weak.
Sollux, I assume, is a homebody. He is the admin of the forum everyone has met on, and likes dealing with GPS units. Brings in computers and stuff, but I really can’t see him doing a lot of traveling unless it’s him watching and reading.
An adjustment for Tavros, when he isn’t risking himself running with the bulls, probably loves hot air ballooning. Fly, Pupa, fly~
Anyone have other ideas?