Lifer you are blessed to have the run that you have. Our two runs that come closest to your 600+ miler is Knx-Nas-Knx-Nas-Knx= 660 daytimer starting at 11:00am, and the Knx to Wye, Winchester meet, Wye to Knx, Knx to Cor. Cor to Knx= 612ish night time. We also have three runs with two stops that get between 386 and 468 miles a night, 9.5-10 hrs to do it.
Phillipians 2:14-15 Do all things without grumbling or questioning, 15 that you may be blameless and innocent, children of God without blemish in the midst of a crooked and twisted generation, among whom you shine as lights in the world.