Hi, Chrash,
Zeldrak is spot on—Honorbuddy should have no problem being used with USB drives. He makes an important point that the machine hosting the USB drive should have the .NET dependencies already in place; otherwise, Honorbuddy won't work on it.
It would be a good idea to place a copy of the installer on the USB drive, also. Unlike the .zip file, the installer will make certain the necessary .NET dependencies are present and intact. You can use the installer on a hosting machine that doesn't have the necessary dependencies already installed.
You may also want to configure Honorbuddy to place its mesh files on the USB drive, also. By default, they will be stored in the %LocalAppData%/Bossland/Honorbuddy/Meshes/ folder. If left at the default location, it is not conducive to portability.
cheers,
chinajade