The last few days I checked the remaining three traps. Nothing. There didn't appear to be any new mouse droppings.
This morning I resolved to inspecting every possible square inch of the car. There is the faintest smell of death. Faintest.
Under the seats, nothing.
Because exhaustively already I had examined under the driver side dash I then removed the flexible, dark colored, panel from under the passenger air bag. It is affixed from the underside with two black plastic screws with the back and side edges of the piece tucking up under everything. In any event, the removal of that panel revealed more mouse droppings and, knowing there's no way the two traps made it out of the cab, further I explored.
Employing a telescoping mirror and a couple of lights tucked up under the dash revealed a mouse face and one arm. Contorting my body and on my back I used a grab tool... about ~2 feet long... push on the red cap at the top of the tool and out pops four... five fingers. When you release the button the fingers grab and you remove the tool with the item caught within the grasp. That tool.
I've pulled and tugged. It's not easy being on your back... trying to keep the telescoping mirror and lights properly positioned while navigating the grab tool pointing it in the opposite direction of what your mind is telling you knowing you've got to keep your eye on the mirror.
I've had no luck pulling it out. I suspect that behind it is one of those facking traps that went missing. My wife is going to bring home some surgical gloves and knows that it may be her small hands that'll be reaching up under the dash to connect with the mouse. My hands won't fit past the white box under the dash. I believe her hands should slip past that box and start grabbing mouse, lol. She's going to hate it.
That's the current update, for anyone who has read or contributed to the thread. Continued updates will follow.
