Bob may work, it can live on a flash drive and doesn't need to affect the windows registry so unless you are on a more locked-down computer than I have seen it should work.
TiddlyWiki-in-the-sky works with dropbox.
I'm pretty sure that all versions of node (Tiddly Desktop, node.js, tiddlyserver, Bob) leave traces in the user roaming directories on Windows. Not personal information or anything. But something to keep in mind if you were hoping to leave the desktop 100% untouched.
-- Mark
You can just have the exe on the usb stick, it doesn't have to do anything to the host computer.