If there's anyone storing their RV anywhere there is a WiFi signal here's what I have setup. I use an old smart phone S4 with an APP on both new and old phones. The app is called ALFRED. You also need to log both phones into a Gmail account.
The App turns the old phone into a security camera that will alert you motion. It also has features that allows you to transmit voice, hear noise, switch from front to back cameras, turn on low light night vision, turn on the light, take snap shots & videos. I have mine setup so if someone tried breaking in it would set off motion alert and record it. I also used recently to catch an intruder. He's gone now.
Here's a screenshot of the APP. It's better than nothing and costs nothing.