Most RVs are poorly built. Avoid any RV that has a minimal CCC for its size and weight. You will be buying a flimsy unit has a low margin of safety.
Whatever you estimate as the weight of your personal items, you are likely to be substantially under the actual weight..... clothing, computers, cooking gear, food, tools, hobby stuff, books/maps/travel guides, luggage in case you need to leave the RV for an emergency trip, wheel levelers and chocks, lawn chairs, screen house, etc. If you are careful you are likely to carry at least 1000 pounds of stuff. Be sure to consider the wet weight, not just the dry weight. Consider you might want some upgrades, such as solar panels, larger batteries, a generator and fuel. Add another 500 pounds for those items, and add another 500 pounds for a safety margin. You can easily hit 2000 pounds over the manufacturer's claim for wet weight.
