You might want to consider the Flir FX camera, i can double as a security camera when not used as a dashcam.
https://fx.flir.com/site/flirus/articles/FLIR-Store/10800029
I am not sure if this pretty new camera start to record with key on like true dashcams do, but it is nice that you can relocate it to another place/ housing when you have parked your motorhome and then have it act like a security camera.
Just did a little clicking and reading on the dashcam mount.
"The dashboard mount provides steady footage of events on the road, featuring an internal accelerometer that senses when a car is in motion and activates the 30-minute loop record function. The accelerometer also senses a 1.7g impact and creates a permanent recording that automatically saves the 10 seconds prior to contact.*"
It do loop record but with huge 30 minute files where dashcams use 1-3-5 minute files, but i assume that will be fixed with a FW update as 30 minute files is pretty large chunks of footage to "loose" when the camera start to overwrite older files on memorycard to make room for new recordings.
The outdoor housing provide a IR light boost to 65ft, which should cover the side of your motorhome.
I think most cameras which allso have a suction cup mount will be able to be used on the vertical RV windscreen, and on the normally huge windscreens a suction cup mount wont look so big as they do on regular cars.
