I believe a long time ago I put my entire game folder onto a disc, no so that I could play but so that I could just move mods over and back and what not without having to redownload. The computer was capable of playing it but immediately when I tried to save or load a game it told me that there was no space to save or load.
I'd imagine that it would work with a USB Flash Drive. You'd probably want something in the 4-8 GB range depending on how many mods you have and what not.
"It's the one that says Bad Mother ****er." - Jules Winnfield... Describing his wallet, Pulp Fiction.