It's a pretty simple effort if and only if you have one major enclosing folder within which all of your image folders reside. I use an enclosing folder called Digital-Captures (the exact name doesn't matter). Inside that folder are all of my other folders and subfolders.
So, if I move the main Digital-Captures folder to another hard drive, all I need to do is click on the enclosing folder in LR that is missing. Once I find the enclosing folder, all other subfolders are already recognized and found.
If you don't have all your folders in an upper level folder, I suggest you do so before copying to the new drive. Just make sure you move the folders from within LR and not from the finder.
Jeff, thanks so much for the quick reply!
I wondered if this was the answer, but decided to check with Adobe support before proceeding. As I wrote, the agent told me I'd have to repeat the locating process multiple times, which just seems too laborious to be viable. I'm glad you suggest otherwise.
My folder hierarchy is indeed contained within one single folder, just as you'd described, named in a way that clearly distinguishes it from my processed TIFF files.
Your help is much appreciated. I'll give it a try.
I am extra cautious now after creating a disaster with my library when I first began stumbling around in LR 1. I just didn't know what I was doing, and made a horrible mess which needed luck, effort, and advice from another galaxy to get my collection unscrambled. I just didn't want to create another mess like that!