I chased the West Valley about a year ago (don't know if this info is still current), and found that in the morning a Woodland-based job headed north and a Orland-based job headed south, met and swapped cars at Delavan, and headed home. North of Woodland, the railroad is almost always in sight of Interstate 5, so you can just drive up the freeway until you spot a train. There are parts of I-5 where exits are far apart, so it's better to use the old highway/frontage road for chasing. Once the train returns to Woodland, the local switch crew makes a trip to Davis with the outbound cars. I haven't been to Woodland since then, but I've seen them in Davis several times in recent months, and the power has been all gensets.

At Suisun-Fairfield, a UP local arrives from Roseville before dawn and ties down on the CFNR main. Around 8am, a CFNR crew gets on board and uses the UP power to take the train to Napa Junction. Another crew works out of Napa Junction, and may go over the hill toward Suisun as well. I went by Napa Junction the other day and saw one GP15 and one genset, although nothing was moving at the time.

On the Westside line, they appear to go to work in Tracy about 6-7am, head as far south towards Los Banos as they need to go, and return. Most of the line is paralleled by State Highway 33, so you can just head south and keep an eye out.