Its so I can carry it around and have all my stuff in one place but plug
it into any PC I find.
Would it, in theory, work? My guess is yes, but I'd be interested in
everyone else's opinions. Thanks very much!
Yes, you can do that.
But, every PC that you want to plug in must support booting from USB flash
disk. (You have to check it out from BIOS setup when you turn the computer
on. I'm not sure if someone will let you do these steps).
You can check the tutorial from Google. I suggest you to create the bootable
flash disk from Linux not from XP.