OvernightRVParking.com is a fee site.
Some folks combine an interest or hobby with locations, like fishing and parking overnight next to bridges, astronomy and good telescope sites, birding and wildlife areas--a rationale for being someplace. Maybe real estate surveying/investing and vacant lots/stores.
More extreme--mobile business (some poster or blogger had a telephone number which went to an answering service for his business; other issues like insurance, other commercial vehicle parking prohibitions, tolls--so removable magnetic signs). So if pet related, park near pet stores. Sports related, near sports stores. Etc. To cut down on interest, business might be pooper-scooper, diaper, etc. Probably more for urban stealth camping.