Starting at the scale is the best thing to do. Just remember the posted weights on campers can be way off and by way off I mean several hundred pounds. Only you can decided what overloaded is for your truck. Illinois will ticket you for not having that safety sticker if you have a D plate. They may also ticket you if you go over 12k IF they have some reason to weigh you. Since we both are in Illinois we know they are desperate for money. If you are really concerned about insurance talk to your agent. Ask as many questions as you want there are plenty of people here happy to answer or should I say give opinions on them.