Wow, you are taking your restoration very seriously with all the right details Steve and I admire that greatly. Keep the updates coming!
Thank goodness #3035 spent it's entire life in the dry CA Central Valley before I acquired it. While most of the interior was burned to a crisp, at least I never had to deal with a bit of interior (or exterior for that matter) rust. I never hooked up my dash speakers to the Regency scanner but sometimes wished that I had over the years as the output would have been louder than just that coming from the scanner itself. It really only mattered when I was on the road where I like to keep tabs on the car-to-car chatter concerning my presence out there.
The output from the scanner itself is sufficient at shows and events to simulate radio traffic and I never hooked up my Micor broadcast radio as well. I always program my scanner for all the areas I plan to travel through when I'm in transit and make sure I have the local frequencies on when I'm showing. But I have to tell you I don't hear near the radio traffic these days as it seems more and more communications have moved over to the CAD system.