You'll love it! Noise isn't really bad, and you don't tend to hear "normal" activity, but if there are some rambunctious kids above you, you'll hear some bumping and thumping footsteps. You just sort of have to hope that you get a quiet couple above you that likes to sleep a lot
I don't recall hearing any other noises that would be enough to disturb you. You can occasionally hear someone taking a shower or toilet flushes, but they're really not absurdly loud. I'm a light sleeper and I still slept through almost everything last time at POP.
There are 4 floors. If you do online check-in, it's one of the check box options. Unfortunately online check-in only allows you to make 2 selections (so 60s and 4th floor would be your two requests). I'm not sure how many things they'll let you request if you call in ahead of time. Keep in mind that most of the 60s is preferred rooms, so sometimes it can be a little bit harder to get that one if you reserve a standard room. I think 60s tends to be the one people request the most.