If you're looking for a meeting place or a good stop around ½ or halfway between San Francisco and Wasco, you can try Oro Loma, CA, which is about 2 hours southeast of San Francisco, or about 2 hours northwest of Wasco.
Other possible places to stop near the midpoint include Wood Ranch, and La Jolla Ranch.
About ⅓ or a third of the way, you can stop at Patterson, CA. This is a little over 1 hour east of San Francisco.
About ⅔ or two thirds of the way, you can stop at Coalinga, CA. This is almost 3 hours southeast of San Francisco, or a little over 1 hour northwest of Wasco.
About ¾ or three fourths of the way, you can stop at Avenal, CA. This is about 3 hours southeast of San Francisco, or about 1 hour northwest of Wasco.
If you drive straight through without stopping at all, the total distance is 258 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 4 hours.