I need advice on how to best handle my installation.
I currently have BB2017 everything pak, on the PG USB HD. I run the program entirely from the usb drive. I have purchased the 2018 UltraPlus upgrade and want to install it on a new external USB drive (the 2017 BB drive does not have sufficient space available. Any ideals on how to best accomplish this?
I was thinking of transferring all of the original 2017 drive to the new external drive, then adding the 2018 install on top of it??
All suggestions are greatly appreciated!

I would copy the 2017 over to the new external drive; then install 2018 on top of the 2017 onto that new drive. It will take a long time to do the copying, so be ready for that.

That way, you'll also end up with a backup drive with 2017 and a backup drive with 2018.