In my MH the step and door deadbolt have a mounted mercury style switch that if the door is not bolted or the step is out lights on the dash.
You would only need one light. Wire all of the switches to ground and feed the other side of the light to 12 Volts. Then if any thing goes wrong the light lights and you know to stop. The lght could be a 12 Volt
halogen that is mounted under the front roof locer and points down, then all you need is a way to reflect it towards the tow vehicle. It should be bright enough during the day to see, unless you have a rock guard. How about a 12 volt
stobe like the younger crowd uses to show their alarm is working?
There is an unused wire in the tow harness if you do not have backup lights. You could wire it to a light on the dash and get the ground feed from the trailer that lights the light fed by the 12 volts from the tow vehicle. If you have working backup lights then you would need to have the light on the front that notified you.