Inexpensive Interior Security Camera
I purchased some of the inexpensive ($20) security cameras from Wyze.com. It is a small, cube-shaped 1080p camera with IR for night visibility. It can send push notifications and a short 12-second recording to your phone if it detects motion. It is powered via a micro USB port and sends data over a 2.4GHz wifi network. While I purchased the cameras for my home, I thought that one could make a nice security camera inside my Sportsmobile.
If the van is parked too far from my home to use my wifi I can use a mobile cellular hotspot device in the van to send the data out via cell.
A number of people, especially those who park their vans away from the sight of their home, probably already do something similar to what I described, but these cameras are so inexpensive it is crazy not to do it. The only drawback I can see would be the need to leave your van's 12-volt circuit powered up and you'd want a means, such as solar, to offset the tiny power demands of the camera and cellular hotspot.