In an area that attracts so many people from other states, Marjorie Wallace is no transplant — she has lived in Pleasanton, California, for more than 40 years and knows the area’s market well. In fact, her family was deeply involved in real estate. Her father was a building contractor, and both parents were licensed real estate agents.

Her father’s business led to Marjorie’s interest in architecture and construction, and her close-up view of the ...