Drive mapping/Moving content between drives

As my media library is growing, I want to move all my movies and TV shows to a 1TB external drive that used to be my Time Machine (now I have a 2TB Time Machine.) Half of the content is on my iMac's internal drive, the other half is on a 500 GB external called "Media Extension." If I close iTunes, rename the Media Extension to something else, then rename the 1TB to Media Extension and move all the files, will iTunes still see all the files that were on the Media Extension? Obviously it won't see all the files that were on the internal drive, so I'd have to remap those. Similarly, will Time Machine add additional copies of all the files or will it see them as the same since they are still on "Media Extension." I might just blow away all my TV shows and movies from iTunes and then drop them back in and wipe out my Time Machine so I don't duplicate all these movies, but just wondering if I can reduce the work in this way.

I'm new to OSX and not sure how all this mapping business works. Thanks.

 

I'm not moving anything in the iTunes folder. These are all files that are outside of the iTunes folder. I copied them to the other drive and renamed the drives and that worked for iTunes. Now I'm moving the other files a few at a time as I do need to delete them from iTunes, move them, then drop them back in. I did find that if you moved movies from another folder INTO the iTunes movies folder you don't need to remap it. It simply sees the file in the iTunes folder.