Hi Carl! I understand that theft (of both tractors and trailers) are a serious problem. I expect that a tractor that has been converter from commercial service would be a less attractive target but, if it's "easy" to take, a thief probably will. I've read that thieves carry jammers that render things like LOJACK (or other trackers) ineffective. 5ers (and trailers in general) are attractive targets too and, MOST states pay VERY little attention to trailers. Apparently, it's NOT difficult to re-VIN a trailer which will make registering said trailer in another state easy.
After 32 years as a Police Officer, I KNOW that there ARE evil people out there and, for a variety of reasons, their numbers seem to be increasing. EVERYBODY needs to be aware of what's going on around them (a concept called "Situational Awareness"). Most people go through life in "Condition White" (ie clueless). Ideally, you want to live in "Condition Yellow" (relaxed awareness). Bad guys quickly figure out who are "easy targets". The more you can be in Condition Yellow, the less likely you are to become an "easy target". A simple nod of acknowledgement (and maybe a smile or "good morning") lets a potential "bad guy" know that you're aware of his (or her) presence and, that simple act can reduce the likelihood of you being his next victim. MOST cellphones have cameras these days. Don't be afraid to use them! If that little voice in your head is speaking up, LISTEN TO IT! Snap a picture of things that set off your internal alarm. If questioned / challenged as to why you're snapping pictures, answer that your friend who is a Police Officer recommended you do so when you felt that something was "off" (you won't be lying, I've just recommended you do so!). DON'T offer money or give any indication of what valuable you might have. If solicited, politely decline and offer to dial 911 for them. If they TRULY need help, they'll accept that offer. If they're scammers, the LAST thing they'll want is having the LAW notified of their presence. Nervousness on their part is a solid sign that they're up to no good; a perfect tome to snap a picture of them, their vehicle / license plate, their accomplices (practice snapping a picture when it looks like you're simply making a call) so they might not realize you're taking their picture.
As RVers (especially full timers), we tend to be trusting of others because we've met so many wonderful people in our travels. The world HAS changed and, we need to adapt, especially to the negative changes. Make sure you're doing the simple things. LOCK doors and compartments. Don't leave attractive "stuff" out when you're away. Talk to your new neighbors. Let friends / family know if / where / when you'll be away from "civilization". Allow trusted people to follow your phone (or other device). Apple has "Find My" (used to be Find My Friends) and Android has a similar App. If you spend a LOT of time "off the grid", consider a GPS based device that will allow you to send a text along with your exact coordinates. I believe Garmin is one company offering such devices. They're NOT inexpensive BUT, they could truly be a life saver. I apologize if I've rambled too long. What I've listed is really just the "tip of the iceberg". Simply be more AWARE will keep you safe MOST of the time but, in life, there really are NO absolute guarantees of safety. STAY SAFE!