Is such a thing possible? I'm quite interested in trying out some of the other mods besides UAP - without having to uninstall my current game. I apologize if this has been addressed; my search turned up no results.
Yep. It is possible. Step 1 - Install Arcanum and patch with the 1074. Step 2- Create new main folders with different names - Car-Arcanum, AWIP, Arcanum1.5, or something completely different. Step 3- Copy and paste the contents of the initial installation (default is Sierra\Arcanum\*.*) into the new folders. Step 4 - Customize as desired. Install the UAP on one, Car-Arcanum on another, etc. Step 5 (optional) - Create appropriately named shortcuts for the modified games. It's that easy. It sounds as if you've already installed the UAP, so delete the Arcanum\Arcanum5.dat and the modules\Arcanum.patch1 files from the copies. This will still leave the no-cd Arcanum.exe but that's actually a bit of convienience.
I figured it might be something like (in truth, I would have no idea what I was to delete), but I wanted to check before I possibly screwed up my installation. You have my eternal thanks.