It will store more than one route - so it's just a matter of breaking down your big ride into smaller chunks, then switching to the next one at a convenient point (control). Hint - name your collection of routes starting with a number - so 1-first bit, 2-next bit and so on.
A few Edge models struggle with composite gpx files (containing more than one route or track) meaning you have to load them in advance as separate gpx files - I don't know if the 200 is one of those models or not, it's a bug, most Garmins are just fine with big composite files.