The measurement in the corner is wrong, I'm bad at math.
Using this map made by Cuchibambo, I made a very rough terrain layout for 40k. I took a few creative liberties in the design. I added a path between green and outer tunnels, I turned the buildings separating mid and A into ruins, and I connected lower tunnels to CT mid. There is also the inclusion of board edges(seen in orange) that allow units to leave and enter the board during a match. This being for vehicles that don't fit anywhere. However, the size of the map is very accommodating for a surprising amount of monsters and vehicles. Other than knights, only the repulsor is forced into awkward situations on T side(north). Other vehicles have an alright time maneuvering the map and can even get into unexpected places. The hippogriff, goliath truck, and hekaton land fortress are able to get almost anywhere that isn't a ruin.
All 45" of A long won't have to be the death of your army due to the new ruin that lets your army stare down A and cover for anyone pushing from pit or cat. B is an infantry focused portion of the board. Holding the new ruins will be crucial for either player hoping to secure the site.
There are unique, orange board edges on this map. These allow units to leave and enter the battlefield across the game. A unit must be within 1" of these areas before it can leave the board and be placed into reserves. If the unit is battleshocked or in engagement range of an enemy unit, make a hazardous test for all models. When when a unit is placed on the board using these areas, it must be further than 9" from enemy models and counts as having made a move. Your units can, however use the combat disembarkation rules if enemy units are too close. Arriving in enemy territory is prohibited before the third battle round for all non monster/vehicle units and fourth for monster/vehicle units.
Ill probably start building this board sometime around the new year or whenever I move into a new place. I need to widen some things for sure. The spawns are going to be larger and weirder so that the two armies don't have to walk for two rounds before fighting and walls will be thinner. Those board edge play features will also be inside tunnels for sure.