If you're looking for a meeting place or a good stop around ½ or halfway between Coronado and Los Angeles, you can try Laguna Niguel, CA, which is about 1 hour northwest of Coronado, or about 1 hour southeast of Los Angeles.
Another possible place to stop near the midpoint is San Clemente.
About ¼ or a fourth of the way, you can stop at Oceanside, CA. This is about half an hour north of Coronado.
About ⅔ or two thirds of the way, you can stop at Santa Ana, CA. This is about 1½ hours northwest of Coronado, or about half an hour southeast of Los Angeles.
If you drive straight through without stopping at all, the total distance is 125 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 2 hours, 7 minutes.