oschavez4, you need this:
https://www.amazon.com/dp/B010XWNFOM...oding=UTF8&me=
It comes with the mount for the back of the trailer, but the package that doesn't include the mount is more expensive. Go figure...
I didn't find the screen to be too small. If anything it seemed too big to me. Took up some real estate on the dash. Finally figured to mount it on the rearview mirror, since that wasn't being used with the trailer hooked up. I did mount it at the far end of the mirror, so I can at least see the hitch in the mirror still.
You can use a velcro strap. I ended up getting two adjustable clamp type mounts and epoxied them together so that one clamp holds on to the mirror and one holds on to the monitor.