2016 Forest River Sierra 378FB, Call or text Jeremy at (231) 299-0302 Forest River Sierra 378FB Layout The Sierra 378FB is a triple slide 5th wheel that has a freestanding dinette, sofa and theatre seats and large entertainment center. The kitchen contains an island with double sink, solid surface countertop, stove, microwave and refrigerator and half bath. The master bedroom contains dresser with a place for a tv and large queen bed slide. A front bathroom has large bathroom with shower, two sinks, large closet with washer/dryer prep and a toilet.