I know this is very old but thought you might like to know this. I'm the granddaughter of Lowell Rathbun Sr. and thought I'd pass along some more information on this. I believe the place you are asking about is probably at or close to the old homestead house on the Rathbun ranch (my grandather named it the Rocking Heart Ranch). The old homestead house is long gone but my grandfather rebuilt a house in roughly the same spot sometime in the 80's. The address for that is around 1281 Goulding Creek Rd and you can see the driveway leading up to the house on Google images.
After Lowell died from prostate cancer in 1993 or 1994, he did leave the ranch to his sons, but he also left the ranch house and a small area around it to his 3rd wife, Liz Rathbun (Denning). Liz tried hard to keep the place but she had her own health issues with Lupus and RA and between her medical bills and the bills left after my grandfather passed, she was forced to sell the house. I'm not sure who owns the house now, but what remains of the ranch still belongs to my father and his 2 brothers, Randy and Michael.