I hadn't even thought to use the saw to make a cut after aligning the rail with the SRK. Thanks for the idea!
I don't know if this would have worked for my job though, as I was truing up a tabletop glue up, and I think the width was more than one SRK length.
For this same project (I'm making a small walnut desk) I'm thinking to start with an over-width front apron piece, clamp it into the rail and use the SRK to true up the edge, then slide the SRK in towards the rail and rout out the drawer holes and maybe even then use the straight bit (thinking a 1/4" bit for this job) to cut the front apron from the rest of board. That way everything about the apron is parallel and square. The arpon remains one piece this way also, as opposed to a more traditional rip, crosscut out the drawer holes and glue back together method.
The front apron piece is currently over length, so and end tearout can just be cut away.