Select portions of song that don't show on PC monitor

I’ve created a practice routine that consists of a bluegrass progression in the keys of B around the circle to Bb. Each progression is 16 bars, so the entire routine extends far beyond what’s visible on my monitor. Sometimes I want to create a loop of 3 or more keys, but I can’t find a way to select that large portion of the routine. Can anyone advise me how to do that? Thanks