The switch I was looking at is this one:
Rubber boot is this one:
I wanted to use a higher quality one since it's going to be used each time you start/stop the vehicle. So I wanted it to last a long time.
@RamDiver Has me thinking about other ideas now, with the mention of the 3.5mm socket angle - which I like.
If I go with something you insert, I don't want it falling out while driving or truck is running when I'm using it after I've used it 100's of times. Have looked at the 3.5mm stereo jacks, power plugs in various sizes, usb jacks, and even RJ45 socket since it has a locking tab. All of which I find pro's and con's with. Like anything you plug in without a lock/clip/rotating position/etc I'm concerned with it falling out. And how many times could you insert something before the socket itself gets worn out? Or the RJ45 option which has a clip, but it's plastic and will only last so many times. And lastly where do I keep this special key? I dunno. Love the idea for sure, but I don't have that approach baked out yet where I've got something I'm ready to move forward on. But something like a 3.5mm connection where there are more than one option to complete the circuit that you decide as a "Key" is appealing to me. RJ45 jack, same thing. Like I mentioned, just need to test it out first with bare wires and then I can fabricate something for the connection part. Ideas welcome certainly!