I have one of those little red blinking lights that are designed to put on your belt as you walk.
When I'm alone in the MH, I put it on top of the dash and turn it on at night. From outside, it looks like the blinking red light from an alarm system.
Don't know what good it does, but it gives me a "false" sense of security and I sleep well.
I've not stayed alone in a Walmart or similar, so don't know how safe I would feel.
I put a curtain rod behind the driver/pax seats so I can pull a curtain closed without having to pull the windshield curtains. That way, if we pull into a place at night for a quick stop, we can just slip behind the curtain for some privacy without being seen from outside.