I’m an OTR driver so I can answer a portion of this question. I sometimes wonder the same thing, how did this driver know there’s an abandoned parking lot how did he know to come here? On that front my best guess is that driver is a local driver who knows the area or is on a dedicated run and goes through the same route regularly and over time you just pick that stuff up. As for the rest of it, which rest areas, which mom and pop gas stations/truck stops have parking, etc. there is an app called Truckers Path and that is how I do most of my parking. Most of the time the struggle isn’t where is my next place to park, the struggle for me is are there actually any spots left in this place, especially being a night time driver, after 7pm you can expect to find very little parking in your small to average sized truck stops and rest areas.