Managing- I've balanced everything really well so far and that's something I usually can't do.

As long as you take the right classes, it's easy to be involved and do well.
(Different types of classes include small seminars with a lot of work and writing, bigger intro lecture classes that are probably more memorization based, sciences/math with labs, language classes and intensive languages, PE classes.... don't take all seminars or all sciences with labs, that kind of idea.)
Last semester I had over 20 hours of class (intensive languages paired with lab sciences can rack up the hours) and I still did things around campus and had a LOT of fun in addition to doing well in school. There are also billions of people (deans, customs people, PMS people, HAs, upperclassmen) that can help you balance your classes and make sure you won't be overwhelmed.
Race/Class interaction- Class interaction was weird for me at first because I'm in the minority on that front, but at this point I have a lot of friends across the spectrum and it's been a legit learning experience. My friends are probably less racially diverse than they were in high school, but I'm pretty sure that was a coincidence- it probably varies more from person to person, but my friends are all very different people.
Traditions... gah!
We've done lantern night, and parade night, plus step sings, so far. Parade night is probably going to be my least favorite of the four, but it was also the first, so it has a special place in my heart. It wasn't bad, but the other ones are just so AWESOME. Lantern night was beautiful. Eerily beautiful. And the step sings are looong but adorable (at least go the whole time for your first). And it's fun to explain to your friends: "Yeah.... my whole school gets together and sings..."
And hell week is just around the bend- so excited!