RVs can be far less of a guide than the rosy picture that you have found. We have a title of land that has no building permit. When we subdivided it off, we were told that we would have more chance of putting a quarry on our land than a house. So we thought "OK, no house permitted so no curtilage in the valuation". Even after protests we still have to pay rates as if that block had curtilage entitlement.