Help with organizing my music library mess

Hello, fairly new the forums.  They have been of great help getting me up and running with a HTPC.  I’ve done some looking around, but figured I’d ask some suggestions on this topic.

So I wouldn’t say I have a problem, just an enormous task ahead of me and looking for suggestions since I’ll only have the initiative to do this once.  I have about 3000+ songs in my MP3 collections from a fairly wide variety of genres and artists.  Up until now I’ve just kinda kept these in a fairly unorganized folder structure based on genre and timeframe I downloaded them.  In some cases I have them organized by artist, but not album, and generally the ones I like most are all in one folder with various artists and genres mixed together.  Many of these are old and have no or an incomplete id tags and album art.  Some are likely duplicated where I may have a downloaded an MP3 and ripped the whole album later.  I’ve liked (or at least used) this method on the PC because I can find them easily.

So now that I am migrating to VMC, my music shows up as a mess under my music library.  I have many genres that have only one or two songs in them.  In some cases, under genre showing by albums, I have two of the same albums shown, while in the unknown album I have 100’s of songs.  There are duplicates of songs, etc.

I guess I’m looking for suggestions on how I should go about organizing this.  Some general questions I have:

-Can I have all of one genre under one folder, or do I need to organize it all by artist and album?  Not sure I want to do this, but kinda seems like it’s the way things are going, this would be a ton of work for me as many I don’t know what album the song is from and it’s not in the ID tags

-I’ve been using tag and rename to fix the tags and update the art, but this has been taking a long time.  All my music would literally take me a year to update here and there when I have time.  Is there a faster way to determine and update the album and art in the tags?

-Does media center organize by genre based on the ID tag?  I’ve seen albums in more than one genre, but could be because of different songs from the same album have different genres in the tag.  Plus the issues I mentioned above with 1 song in a genre etc.

-I have an archive folder with all the older (by download or rip date, not album release) music sorted by genre which accounts for 2/3 of my collection.  They are older mp3s with incomplete tags.  I’m OK with work arounds here since this is not music I listen to regularly anymore.  For example I have an 80’s folder.  Can I just change the tag genre to “80s” for everything in this folder so they all show up in one genre in VMC instead of mixing with current music?  I’d be OK if these tags were not perfect for album names etc.

Sorry this is so long, but I want to do this right the first time, so any suggestions are greatly appreciated.