We use a website to help us pick free and safe spots to spend a night:
www.overnightrvparking.com They also have an ap. It's a subscription of $25/yr but it gives reviews besides just telling you which places allow and which don't. It is crowd sourced, and if you review a new spot, or one that hasn't been reviewed for awhile, they add to your subscription.
If previous reviewers indicate unease in a location, we will skip that one. They are map based, and often list places we wouldn't have thought of, like a grocery store or Lowes.