I think on my first playthrough, the only things I had to go back and hunt were...
-Grognak the Barbarian
-Pugilism illustrated
-Holorifle mod (forget which, but it was on top of a roof
-Automatic rifle mod
-Bear trap mod
So it actually didn't take that long to hunt it all down. I'd explored every nook and cranny as I played it, knowing there was probably lifesaving loot in some of them, so I ended up finding just about everything. The ones I listed above are in such deceptionally-empty places which is why I missed them.
I think my favorite part had to be when I ran my ass off to try and get the Repair skill book when I had my collar on, only to realize when I activated the terminal near it that if I did NOT succeed in hacking it, my head was gonna explode. Needless to say that was my most carefully thought-out hack attempt ever.