Originally Posted by mattp1987

Sometimes you can pull up these routings on Google Flights, Hipmunk, or Kayak and use their link to DL.com. It might require their multi-city search feature. Hipmunk uses the same back-end as Matrix, so the same advanced routing codes should work. I've never really done this for domestic, but I've used G Flights a few times to put together international itineraries where I wanted to maximize my 23:59 connections.