The DC jack on the Midland WR-100 is 12V and tip positive. I purchased a DC car power adapter for this unit today and confirm that it works. It will be replacing my former weatherband radio which did not tune well. This one is digital and performs better.
The bad news is that I don't know if a marine head unit would perform better? It would need to have its own GPS, or actively scan for the nearest station and interrupt whatever I'm listening to when a weather emergency occurs. I just haven't found a head unit like this.
Today, I purchased an eyelet to screw in to the tailgate latch plate that will route my paracord so that I have an easier manual release. Also, I purchased some silicone. The plan is to drill through the hull of the battery and spare tire compartment to run my trailer lighting cable out of the car so that I don't have to slam it in the tailgate door anymore. On the trailer hitch, I'll be installing a mount for it. I also purchased a small flashlight with a key ring small enough to to fit the loop hole on the HHR's manual tailgate release.
All of the trailer lighting connectors that I previously prepared for the tounge, separation point and lighting had to be replaced. I didn't keep track of the color coded wires that I snipped off and thought that they were irrelevant.
Earlier, I found a set of orange side marker lights that have and actual ground wire.
The drilling is going to require lifting the back end of the car up. The only way to safely do without a lift that on my Chevy HHR LS is to back it up on ramps. So, I got those out of storage today, as well as some hiking gear. Once I get The Cramper's equipment out of there, Storage B will be pretty thin.