Like said above, driving it down the road verse trailering changes stuff. And ours, a firetruck (from a major city to boot) adds to the decisions.
Safety becomes an issue if driving down the road. We changed our "Service Only" brake chambers on our '57 B85F to have spring brake chambers on the rear. We are planning to drive the grand kids around and that was a no brainer. Yes, very visible and had to add the yellow knob on the dash. The QRV is hidden under the firetruck "turntable" ( the equivalent of a fifth wheel but is for a permanent mount fire trailer (Hook & Ladder)).
The firetruck dual starter buttons , the two separate battery systems and the run the ignition off "Battery A or B" switch is a discussion Jack and I have repeatedly. I'm leaning towards keeping it, but battery technology today verse 1957 makes it almost not needed, especially on a truck that's no longer on emergency response duty. So, keep it because it's sort of neat, or get rid of it (or not use the buttons but leave them in place) because it's not needed....??
Paint..... On a working truck, unless it has Historical value (like a UPS truck, or the Bethlehem Steel truck at the Museum), it's a new owner choice. That includes doing one of those patina looks. On ours, as a firetruck, a previous owner (Mr. Barton from East Hampton, CT) repainted the truck and put his own lettering on it. "Barton" on the hood, and "Ladder 1" over "East Hampton" on the doors. It originally had "Boston" "Fire Department" on the hood, and "Ladder 11" on the doors. After a bunch of talking, where I really wanted it back to the Boston Scheme, verse a "Mack Family" scheme, I think we are headed to the Boston scheme. More Historic, and a conversation starter. There is a thought to have a list of owners somewhere but that is far from important at this time.
Trolley valve...... the trailer is long gone, so it does nothing (lines are plugged). Jack is leaning on getting rid it. My plan is to convert it to a type of manual Hill-Start (Mack "Grade Gripper"). Our treadle is a single circuit type, so easier to work on. I picked up a double check valve at the Mack Museum garage sale this past October. It has 2 inputs, 1 output. where one input shuts off the other. This will prevent the Trolley valve from venting thru the not pressed brake treadle and venting air and, vice-a-verse, when using the brake pedal, air venting out the trolley valve vent. That's going to be a hidden upgrade, so not many people would understand it's there. Note, I also picked up a modern 2 circuit treadle and a governor (compressor un-loader) at the garage sale, both NOS. Converting to Primary and Secondary air....... talk about a lot of work. Good work, but very tedious.
Then there's the wiring. Restore to original functions or make it more modern. It's mostly hidden so only some people will notice. For ours, Doug Maney, the curator of the Mack Historical Museum, said to me "Tom, you will find that firefighters think they are electricians, but they are not". Need I say more. In the rewiring, I keep wanting to make it more modern (the electronic tech in me) , using more relays to shut things off when the key is turned off (yes, adding a key is another upgrade for a firetruck). Jack, the Master Electrician, wants to keep it simple and that means more original.
Wheels, Update or keep original. That's more on how much you want to spend. Shiny Aluminum, modern size rims, etc etc. We have 11.00-20 tires on the 3 piece Budd rims (sliding ring (bead ring) that hold the split lock ring in place). The price of 20 inch truck tires is rather high now a days, because they are now custom ordered at most places. So we are converting to 22.5 inch Budd rims. Wanted the "Five opening" rims, but they are hard to find. Picked up 6 Accuride "Two opening" rims at a great price. But now I have a lead on 4 "five opening" ones, and if we get them, 4 of the two opening rims will be available. We now got tires for the rims. Just a matter of sanding and painting the rims.
Dream: add a second row of seating for the grandkids. That will be a very noticeable modification. But, depending if a lead on another "open cab" cab pans out , it could look awesome and raise the value. And I would like to make it a bolt on addition, so it could go back to a Tractor-Drawn-Aerial-Ladder if someone "gives" us a tiller trailer and a free space to store it.
So........ the decision seems to be a Concourse Trailer Queen or a Driver. We're going for the "driver" restoration.