Questions about gmod 13

Ok so I was wondering if Gmod 13 will be able to work off a flash drive without steam installed, if it isn’t can garry make it possible? I would pay just about anything to be able to have it mobile because I have a 250GB Harddrive and would love to play it on other computers like at school, because my school doesnt allow us to download steam and mostly everything even the fourms are blocked lol so yeah.
Also what are the physical changed to gmod 13 besides the q menu, startmenu, and the physgun color things.