WHITEWATER, Calif. — There was the five-mile dusty drive to a remote wilderness reserve on the outskirts of Palm Springs, to talk about her efforts to protect the pristine deserts and mountains that make up so much of California.

A few days later, it was off to Salinas for a tour of a mushroom farm with members of the powerful United Farm Workers. And on Thursday, Senator Dianne Feinstein, the California Democrat, was posing in front of a C-130 firefighting air tanker outside Sacramento as she got a briefing from state officials about the coming fire season.

At a time when other members of this state’s Democratic old guard are moving toward retirement, Ms. Feinstein, 85, is running again, closing out what will likely be her last campaign with a statewide tour that has all the markings of a career valedictory.