I never bother to fill out things like the year field on the playlists. Only on the song files themselves. It doesn't take that long to sort albums by their dates, just view details, sort by position, and alt-drag the albums up and down in the list.

Of course, I don't even bother doing that. Having the albums in year-order isn't something I get anal about. As long as the songs are tagged by year and display the correct year, I'm happy.

A shortcut would be to use Jemplode's soup views, I suppose, which in theory can create that kind of stuff based on the tags.

Regarding your other question, I believe (not sure) that the hidden folder "unattached items" is number 1. I seem to recall that it's hidden because people asked too many questions about it or something.