If you're looking for a meeting place or a good stop around ½ or halfway between Coronado and Long Beach, you can try San Clemente, CA, which is almost an hour northwest of Coronado, or almost an hour southeast of Long Beach.
Another possible place to stop near the midpoint is Don.
About ¼ or a fourth of the way, you can stop at Carlsbad, CA. This is about half an hour north of Coronado.
About ⅓ or a third 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 Lake Forest, CA. This is a little over 1 hour northwest of Coronado, or about half an hour east of Long Beach.
About ¾ or three fourths of the way, you can stop at Santa Ana, CA. This is about 1½ hours northwest of Coronado, or about half an hour east of Long Beach.
If you drive straight through without stopping at all, the total distance is 118 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, 54 minutes.