If you're looking for a meeting place or a good stop around ½ or halfway between Lockeford and Sunnyvale, you can try Altamont, CA, which is almost an hour southwest of Lockeford, or almost an hour northeast of Sunnyvale.
About ¼ or a fourth of the way, you can stop at Lathrop, CA. This is about half an hour south of Lockeford.
About ⅓ or a third of the way, you can stop at Mossdale, CA. This is about half an hour south of Lockeford.
About ¾ or three fourths of the way, you can stop at Scotts Corner, CA. This is a little over 1 hour southwest of Lockeford, or about half an hour northeast of Sunnyvale.
If you drive straight through without stopping at all, the total distance is 92 miles. The distances shown above don't include local roads to get into each town, so if you're planning a long road trip, make sure you factor in traffic and road conditions, rest stop breaks, and interesting detours along the way. If you're in a rush, you can do the trip with zero stops, and your total travel time would be around 1 hour, 41 minutes.