I see a problem, related to your specific example in your question.
In a truck stop or even in a Walmart parking lot, that would probably be just fine. Your example is at a "rest stop or something like that."
Rest stops, specifically, have an earned reputation for risk to personal security. They are more or less risky depending upon which state and where in that state you are. Arguably, they are safer, the further you are from larger cities. They are more risky at night than in the day time. They are more risky when few vehicles/people are present, safer when crowded. I have used them, mostly for brief stops. Almost never at night, and only then if there are quite a few others there.
I sleep quite comfortably at truck stops. I haven't yet, but would be quite comfortable at a Walmart - etc, depending upon its location.
If you are in a TT, you have to get out and move to the Tow Vehicle, in order to get moving, again. In a motorhome, turn the key and go. You don't have to get out, at all.
IMHO, motorhome wins, again.
Ray D ;D