Far removed from its days as a synonym for "huge Class A motorhome," Winnebago is now known for a diverse lineup of on- and off-road RVs of all sizes. Building out its "Backcountry Series," the company adds its most ruggedly luxurious offering yet: the Arka truck camper. This off-grid expedition behemoth is prepared to spend up to 2 full weeks at a time in the deep, dusty backcountry. It's sure to have the Earthroamers and Krugs of the world pee…