Try to maintain a continuous line. If you create ‘hardspots’ where the Axis can get ZOC on the hexes your units need for retreating you’ll find your tactical retreat hasn’t preserved anything.
I was indeed mistaken each trunk counts as 1 unit as opposed to trucks working like supplies. You are not allowed an unlimited number of trucks per hex. :oops:
You would have to land supplies at the beaches and move them to the front line units. Units would have to be able to move out of zones with other units. The whole “locked in combat” aspect of D-Day is not in keeping with most of the mechanics of BOTB.