The Black Series HQ12 ($50,000, pictured) weighs 4,422 pounds, is 19 feet long, and may be the most capable adventure trailer on the planet. The all-terrain chops start with the suspension, which uses four shocks instead of two. Each wheel moves independently, smoothing out bumps, and a burly galvanized-steel frame and diamond-plated rock guard add protection. Inside, a full kitchen, toilet, and shower connect to a 50-gallon freshwater tank, with an additional 16-gallon container for drinking water. A furnace and air conditioner, dual-pane windows, and insulation keep you comfortable, and there’s space to sleep four. The electrical system runs on shore power or two 150-watt solar panels and a battery. Our favorite feature: the second kitchen, which slides out of an exterior compartment and has a three-burner stove, sink, and…