USED RVS, TRAVEL TRAILERS, TOY HAULERS, 5TH WHEELS, AND CAMPING GEAR FOR SALE NEAR SIOUX FALLS, SOUTH DAKOTA 2011 Keystone RV Cougar Half-Ton 31SQBWEFor years RV buyers have made Cougar #1 in its class. The reason? Cougar offers you more features, more innovative floorplans and higher quality, all at a popular price. With unique models like the Cougar Den, your choice of several bunk house models and toyhauler options there's bound to be a Cougar that's perfect for you.