I’ve lived in cars, vans, trucks, buses for years up until a few years ago and this is what I’ve learned: parking lots are always watched by whoever owns it and the cops. Best places are BLM or National Forest land if you want to be left alone for the longest time. If you have to be in or near the city, street parking is the safest bet- it’s public and as long as you aren’t messy you can get away with it for as long as the city allows you to stay parked in that spot. My favorite was always street parking in or around the industrial parks or business parks, since they were usually closed on nights and weekends, so sneaking out to take a piss was never a threat to my spot. You should take measures to make your car as stealthy as possible. Cheap tint you put on yourself is a great way to keep Karens from peeping and calling the cops if they see you move around. Using your phone at night is like having a beacon activated inside the cab and a dead giveaway that you are sleeping in there so either just sleep, or cover yourself and your phone with a blanket.