Actually I even tried hooking up a usb hub to my Surface RT and had a mouse, keyboard, printer, and camera hooked up at the same time! And it all worked!
You can absolutely hook up mouse to it. You can hook up printer to Surface RT and thousands of other USB devices, not to talk about atom and core Windows 8 tablets were you have access to drivers.
With only one USB port, I personally think you're better off using a Bluetooth keyboard and mouse, personally, but like the others have said, any will work.