When it comes to overnight parking, you want to be somewhere it doesn't look odd a vehicle is sitting there at 3am. Places like hotels, car lots, parking garages and apartment complexes (those that don't require usage permits, anyway) are generally more well lit, fairly good chance of having security cameras, and since you won't stick out like a sore thumb, less likely to get hassled.

Try to avoid parking immediately alongside busier streets, particularly with more pedestrian traffic. Granted, big differences, I live at this apartment complex and I have just a regular ol car so people can easily see me when I'm parked nearby the road or alongside the buildings. I'm just a tired ass lady who sometimes passes out the second I park at home so most of the hassling I've received has been out of concern from other residents. They either knock on my window to make sure I'm not dead, or call emergency services. Have had 3-4 instances of each. And then 3 other times, approached by random dudes on foot asking for a ride. Definitely made me feel uncomfortable, enough so I keep a knife in my car now, but they did eventually accept "no" for an answer. I would think a van without windows in the back would help mitigate people trying to approach for whatever reason.