DESIGN YOUR NEXT HOME: "The Harriman Plan" to be built by RG Custom Homes on Lot 153 in Whistle Stop Farms Subdivison. The development is designed for buyers to customize the home they would like to see on the lot. The completed homes must go around $750,000 and above. Rob Galbreath is a 20 year veteran builder of Williamson County. Call if you're interested in designing your next custom home. The details listed below describe the home to be built on lot if not pre-sold.