The fictional Ponderosa ranch included the entire north shore of Lake Tahoe and yes, the TV Ponderosa was in Nevada.
I remember one episode where it was stated that the Ponderosa was “1000 square miles” in size. A square mile is 640 acres, so the fictional Ponderosa ranch would have been 640,000 acres.
True, and there is no way you could/can ride a horse from the ranch house to Virginia City for lunch - unless you start the day before. Not without killing it.