I did a set about 4 years back...the vent window comes out last. There are screws everywhere. My '73 doors had three screws for the window crank, three screws for the door latch, the vent has a screw or two up the front door post, one is almost on top. Theres a screw or two for the window track in the back, above the latch...there are several more of them on the inside for window tracks....Lower front (those are the bottom of the vent/front window tracks)
Anyhow..its alot more than 3! If you see a bolt or screw, take it out! You should be able to leave the door handle and latch in, but to get at the vent, you have to take everything else out. The vent is molded into the front window track...it goes way down in there...
BlazerMan