DJing from USB flashdrive

So unfortunately my hard drive on my mac is jammed full, mainly because of how much music I have. I decided to buy a couple 128 GB usb flash drives in which I was hoping I could transfer all of my music onto, and delete it off of my computer to free up a ton of space. However, I'm worried this will cause complications with my ability to DJ in Traktor.

I just backed up my entire iTunes onto my external, as well as one of my new flash drives. However, I'm still hesitant to delete all of my music because I don't know how it will effect life in Traktor... When I DJ i typically play from my iTunes tab within traktor, where I keep all of my setlists (as playlists within iTunes).

My question is, will I still be able keep everything as it is currently in my iTunes, but directing it from my USB flash drive instead? and can I still access all of my current playlists and iTunes music in Traktor but from my USB stick? I don't want to mess everything up but I really need to free up space on my Mac.

in other words, can my iTunes be empty until until I plug in my USB flash drive, and then all of my current songs, playlists, info may appear? and also in traktor?

I hope this makes sense, thanks!!!

If it was me I would be investing in a bigger internal drive and make it SSD while I'm at it.