You can delete a track or delete/rename an entire album/collection using the option button.
I have not found a way to rename an individual track or add a track to an existing album. I have to wipe and re-import the whole thing.
I'm finding it much easier to just put my stuff on a big USB stick and play it directly from there. Playing from USB remembers the random setting (playing from HD does not) and I can modify the stick anytime I want on the computer.