The guy I used to work for had a customized '50 Ford back in the late 50's, he said his was controlled by a long choke cable that ran up beside the back seat. I think I'm going to do that on my '51 Mercury. Cheap and easy, and doesn't require any wiring or modern parts.
i used a honda trunk catch and cable on my 41 chevy. i mounted the release handle under the drivers seat.
After my third solenoid and crawling through the back seat once to get in the trunk..... I use a bear claw latch operated by a cable. Hasn't failed me yet.
My shaved '56 Ford convert had a choke cable that was located behind the license plate door, installed in the indenture next to the gas filler tube/cap. Out of the way, and placed the 'operator' at the deck lid! Per @chopped51's post: A bud with a chopped carson topped '41 Ford ragtop had his battery go dead at a Ray Charles appearance in '58. No door solenoid action, just some weak buzzing... Idiot was gonna slice the top to get in! I was a skinny kid, so was able to reach up into the engine compartment and pull the hood cable. Jumper cables got the battery up enough to open the door. That week we ran a choke cable to the door latch, drilled thru the door frame and front jamb at the A pillar, secured in the lower inner fender well. Had to lay down to reach it, but great backup system.
I like the gas door idea, that'd save me from having to dive into the car to hit the cable. I might adopt that.
Let me just ad a laugh here on this subject. We had a guy drop off a 57 Chevy Delivery (full on $80,000 custom car) in our show room to sell. It had an Alpine Digital alarm and control system in it. Every handle on the car shaved, windows up and all the doors closed. It sat here for 3 months. Last week he came in to get it to take it to a car show but the little remote control only made the car beep twice. It would not roll down the windows, pop either of the three doors etc. After spending half the day here trying to break into the car with as little damage as possible, they found the system had been turned off with a toggle switch under the dash. It was a mess. I guarantee you, a week later, that puppy has some kind of "manual" over ride of that system installed (I mean a cable somewhere)....LOL
I used a long Lokar cable with a small under dash lever on the inside and a secondary choke cable hidden under the rear . Two ways to get the trunk lid open from inside or outside the car- no solenoid , no problems getting to the battery ( in the trunk) if it goes dead .
I used a cable and ran it thru a brake line . I ran it right next to the driveshaft hump and stopped it just under the front seat,works great.
Why not just use a power trunk latch used on most GM cars from the 90's on up. Why re invent the wheel when they are available at every junk yard in the country.
I used a gm hood latch and cable setup. I made a handle for it that is hidden behind the license plate. You'd never know its there unless you saw me use it.
Never was much of a fan with solenoid switches. I prefer mechanical devices. A trip to a bone yard will get you lots of options. 30 years ago I used a simple bone yard mechanical latch from a Subaru. I modified the trigger lever rod to exit below the rear pan where it is not visible but easily accessible when you reach down to lift the trunk lid. My latch could also be operated by cable or by a solenoid if I chose to do so.