Marin County authorized the purchase of the Donovan parcel in Point Reyes Station on Tuesday, agreeing to pay $485,000 for the lot at B Street and Highway 1. Of that cost, $35,000 comes from a quarter-million-dollar fund devoted to West Marin visitor facilities set aside in 2019. The county will undertake a public process to determine what to do with the property. “I think there is an assumption that visitors as well as locals will…