Topock is on the Arizona bank of the Colorado River southeast of Needles, CA. Nearest builders would be from Bullhead City (about 25 miles), Lake Havasu City (about thirty miles), Kingman (about forty miles) and Needles about ten miles as the crow flies but twenty miles by road. No industry, commercial (except rental parks for snow birds), etc in the Topock area. Although it is about five miles north of I-40 just before you cross the river, that five miles is a narrow, winding road. So you can't get there from here and construction workers would have a lot of travel time. Most of the materials would have to be hauled in from Las Vegas, or wait for a local supplier in Bullhead City or LHC or Kingman order them and then wait for shipment. So a price per square foot to construct would have lots of factors that building in a larger town wouldn't have. Marshall & Swift show about 2-3% more than Phoenix or Tucson. And the land was probably more expensive than a similar lot in Phoenix or Tucson, specially if it is near or adjacent to the river. Private land is very, very scare in that area. Most is federal, state or Indian reservation.