You can drag/drop the folders in the library folder tree from one hard drive to the other. Sometimes it seems that this method skips some of the images. The other alternative would be to use your operating system to move the folders to the other hard drives, and then follow these instructions to relink them:
The instructions are for an older version, but the principle is the same. Using either method will retain all of your adjustments as long as you continue using the same catalog.
In theory, you can move the folders in the Folders panel. However, in practice LR is not a file browser and seems to not handle large numbers of files well.
Your best bet is to use your OS tools (File Explorer or Finder) to move your directory trees to the new drive (do not change the directory structure), then use the "find missing folder" or "relocate folder" functions in LR to reconnect then moved folders. (See Jim's link.)