The 2006 Cambridge fifth-wheel series, featuring floorplans with three and four slides in 34- to 38-foot lengths, represents Keystone RV Co.’s first entry into the high-end towable market. The Goshen, Ind., manufacturer’s four-season fiver, retailing from the mid-$60,000 range, is engineered to withstand temperatures as low as zero degrees Fahrenheit. Exteriors offer a high-gloss gelcoat fiberglass finish and hydraulic landing gear. Interiors sport solid maple woodwork and cabinetry, upgraded lighting, flat-floor master suite, king-size innerspring bed and a hidden safe.