I can answer some of these-the accelerator return spring is connected between the bottom hole of the cross shaft (assembly that runs from the carb, down to a bracket on the firewall, and then down to the other side of the firewall from the accelerator pedal) to a hole in a small bracket on the firewall about where the bottom of the pedal is on the other side. If this doesn't ring bells, I can send a pic.
Antennas can apparently be mounted on either side of the car (I've seen many examples of each) on the crest (or just down from) of the fender a few inches out from the intersection with the front door.
Shocks are pretty generally available (NAPA, JC Whitney, Rock Auto, etc. ) Some of these sites list them as being for Kaisers, others (Whitney) don't but list them for Studebakers, with which they interchange. Rudy Phillips also has them.