You could have a momentary switch running from the front of the cab to the computer, to power on the computer and hacked power strip (like powered speakers and lights all come on). Then another momentary button right next to it that turns on the TV (the button wired to the TV's power button's solder points)
It's a 2 button affair, but that's not too bad. At least it's all outside of the cab and not hard to reach.
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I wonder if a single momentary button can do double duty ?
For example, one button on the front of the cab wired right to the TV's PCB. But it's also wired to the computer's mainboard. So one button press turns on the TV and the PC, the PC being on activates the hacked power strip which turns on the speakers and lights.
Hey that might work