Accessing the cab side of the door jamb

[Wizo]

Greetings Dave;Ron here from down in Tacoma.I realize you don't want to do a conduit and would rather do contact switches but either way your in for a somewhat tuff job.I opted to do the conduit. I myself could not find any way into the "door jam". You can not get to it from the vent box.It is actually the bottom extension of the A pillar. Plz trust me I know. One of my upper door hinge nut plates fell down all the way to the bottom. It took an hour with several biers and safety wire to fish it back out. Royal PITA.
I cut a square hole in the door jam from the outside (with door removed) to access the area behind where the push pin light switch would be mounted.
I also drilled a 1.5 inch hole in the door jam behind the dash to run the wires through. I used safety wire to fish the wires back through. You will want to put a rubber grommet in the hole behind the dash to protect the wires. I hope this helps you out. PM me if you wish/need to. Take care.