If you are near a city or have your AS parked in your driveway in town... you have the highest risk of being a victim. Boondockers, or in my case a Rockdocker, I have NEVER had an incident in the back woods/deserts.
The number one piece of good advice given to you is to have one of the many good methods to lock your hitch. Any RV sales business will have several to show you and some might fit your AS better, so check them out.
Number two. Put your name on water jugs, your propane cylinders, lawn chairs or anything else you might want to deface with your name. An inexperienced thief is less likely to take items that have identifying marks. A professional will get what he wants and you will not realize what has happened.
Number three. Park your trailer, when boondocking, where it CAN be seen. A thief does not know what your tow vehicle looks like. If the thief does know what your vehicle looks like, the next vehicle he/she hears could be you. Two or more parked trailers discourages the thief that needs to take time to look over the options...
Number four. Personal protection. One earlier message mentioned a firearm as being a silly option. That is true, if you have no experience handling anything this extreme for protection. The majority of instances you would WISH you had a firearm is to discourage a bear or mountain lion that is looking at you or family as... lunch. I have NEVER in forty years of camping in the back country, wilderness or sitting on the couch at home needed a firearm. Be it a pistol, rifle or shot gun. Having a firearm will give you a false sense of personal protection, if you do not have any experience using it. Your worry is least for "bad people" but more for camping in the company of wild predators.
Number five. Personal protection. My first line of defense is my walking stick. Those hikers who carry the expensive aluminum hiker's ski poles, fine. I am not criticizing you. I and my wife have four foot long walking poles made from a straight branch, small tree or even to found in a beaver dam or log jam along a river. Peel the bark off and decorate to your heart's desire. It must be comfortable for your hand and the larger diameter you can handle, the better. It will make even a bad guy look twice before he messes with a hiker and his STICK. It works well for dogs that want to chew your pants leg and at least you have something to swing for protection. Aspen is poor. Pine is excellent. Oak, go for it. Walnut... you are a dangerous person.
Number six. You are more at risk... GETTING LOST. Always carry a compass and keep reminding yourself where your camp is. A GPS is the best out door invention since the compass. You say that YOU cannot get lost! Then you have not been in the forest. EVERYONE has found themselves lost at least once in their lives. It is happens to the best of us... even myself and the COMPASS is always RIGHT.
Number seven. After a few camping trips in easy to find excellent boondocking camp sites, you will feel more comfortable. Your first trip will be the hardest. It will be the last camping trip of the season that you will find the most rewarding and you will be comfortable with your surroundings, but always alert to what is happening around you at all times.
Number eight. I know... I go on and on. I want you and your family to remove yourselves from the urban mindset and discover what the rest of we boondockers and rockdockers have known for our entire lives! Be well and take that first step this Spring. And by the way, check the air in your tires.