Any tricks to working under ‘71 Duster dashboard?

I have never taken the seat out. How I access depends on what job I'm doing. I generally pull inst' panel, or glove box liner to work through the dash while sitting in the seat(s).
For speedometer cable, If I remove one screw from fuse box and move it a little, remove headlight stem and bezel nut to move that switch a little, I can kneel at the door opening a to put left arm up in there.