What's the best procedure to setup top-rope on a neighboring climb?

There is a 5.11 anchor a few feet over from the anchor of a 5.9. You can traverse over a few feet from from one anchor to the other. What's the best way to setup top rope on the 5.11?

So far what has worked best is to lead with a second rope clipped on to my haul loop but that only works if we have a second rope around.

How can we set this up easily when we only have one rope and no strong rope-gun at the crag?