portable security fencing for rv storage

Harbor Freight has motion sensing alarms for about $10.00 apiece. Put one or two sensor/transmitters outside the trailer with one receiver/siren under the eaves of the house and the other one inside the house. I would put a third inside the trailer with the siren in the house. They are battery operated and run for years on a set of fresh high quality batteries. The siren is really a wailing sound and pretty loud, often that is more effective than a sign or scare lights. Of course a motion activated recording of jacking a shell into a twelve gauge is spooky too.

Enblethen has a good point, a trail cam or a set of wireless cameras with a cloud storage account.