While we take every precaution we can with locking our RV and trailers, the absolute best thing to have is a great insurance plan/carrier. Another very affordable peace of mind item to have is a GPS Tracker. I installed one in our rigs and know immediately if they are moved and can go live to see almost to the foot of where they are.
Was very helpful when we had to leave a trailer in Florida this past winter that was then hauled to the manufacturer in Indiana. I knew where the rig was every step of the way. At home, each unit is set to alert me via text and email if either are moved. The slightest movement or shake will send an alert. We paid $149 for the unit and yearly service is only $149. Totally worth it to me.