Using our Shortstop to cover 2nd base is a very traditional thing to do in softball, but it isn’t always the fastest, easiest or even best method of coverage.
With a runner on 1st, consider using your 2nd Baseman to cover 2nd base if the batter is right handed and probably won’t bunt. It’s often an easier throw for the catcher to make since she sees the 2nd baseman the whole time. It allows the catcher to throw the ball earlier since the 2nd baseman is moving through the throw as she moves to cover 2nd, and it allows your shortstop to hold her position and play the hit ball.