I would recommend using the power button.
Mouse on desk, always move, a 1mm movement will wake up the device, and it will annoying (it will feel like it always wakes up on it's own).
Keyboard is fine, but I am not sure if the keyboard cover will be affected, which might be an issue if you close the keyboard cover and while you transport it, wake up due to a key press. Not sure. While I don't have anymore the SP2 (faulty, going to order a new one once back in stock), look under Device Manager (Start > Type: Device Manager), then go under Keyboard, and double click on the sub items that you see. You should have a tab called: Power Management. Inside you should have an option to make allow it to wake up the device (and it will when you press a key). Try and see.