I'd advise against setting the homepath unless you've got a really good flashdrive. It might just be the vstr command, but my game runs slower with that set. But yes, copying the executables and the basepath to the flashdrive is enough.
If you want all of your binds, maps, and qkey (assuming you have one), or if you just want simplicity, then its probably best to copy the entire homepath folder, but there are more complicated configurations if you want more space available on your flashdrive or if you simply would rather copy one file rather than a folder.
Binds (as long as you don't want to change them as you're playing, but that's a silly way to do binds) can be put in your basepath as base/autoexec.cfg (if you're playing gpp it will be gpp/autoexec.cfg) which will be automatically executed on the game's startup. Any maps (or other .pk3s, but into the appropriate folder depending on the mod) that you want can also be put in the base folder with the game's default maps. You may leave unwanted maps behind to save space. This leaves just the qkey, the copying of which I'm sure there is an easy way to automate, but don't care enough about windows to do.
