You panel owners are very spoiled. The rest of us have to risk a broken neck to get under there!
If your dash is like the AD then maybe this will help. I remove the speaker grill and then work from right to left, accessing everything sitting in the driver's seat. After removing the grille, it is easy to access the speedometer. After removing the speedometer, it is easy to remove the gauge assembly. If you are taking it all apart, removing the light switch from its mounting will give you some slack to work with. Also you might want to remove the mechanical heat gauge from the head and push some of the tubing into the cab.
