Or, do I have to delete and re-find all 7,000 songs in my library manually and one at a time?
This is what you have to do... It sucks, but it probably best...
I have a 100gb at work that is my main listening. I do a lot of TAG clean-up, album pix, etc. to my stuff at work. Every once in a while I'll bring it home and dump the entire 100gb onto the 250gb. I copy over all existing files with my new ones. Keep it all the same.
Then I go into iTunes, delete everything, and then add everything. I usually do this before I go to bed and in the morning it is done.
After that, it is the PITA task of updating Heather's Lappy. That thing does it wirelessly, so its even slower...
But once you get it all done, all your various files and iTunes are all the same...
Good luck!
Terry