None dare call it cheating, but I drove part of the way to the highest point in Orange County.
I started out in the small rural town of Silverado (east of Tustin, if that means anything to you) and drove up Maple Springs Road. I could and should have biked it, but I drove it. After the town ends it turns into rough pavement, and then after that it turns into a much rougher dirt road with plenty of big dips and twists. I was in first gear through much of that. It gets better after a while, and then intersects with the Main Divide Road.
I parked shortly after that intersection and just started walking up the road. I gained at least 1000' so I did earn it somewhat. Before long I was at the majestic, towering summit... actually, Santiago Peak is yet another highpoint that's home to an antenna farm. However, it's a large summit so there are OK parts and you can get a good view over Lake Elsinore and in other directions.
After that, I walked back down the road and did Modjeska Peak, the second-highest mountain in Orange County. It's a much better summit.
The third highest is Trabuco Peak and it's further east along the road. It looks like the way to get all three is to start in Trabuco Canyon and do Trabuco, Santiago, and Modjeska. Whether that's bikable or not isn't known. Or, start at Ortega Hwy and bike up Main Divide. I can't do those now since part or all of the forest is closed after a fire.
Anyway, after getting both peaks, I then went to an OCSC game. I don't at all regret driving behind the Orange Curtain for the two peaks, but I do regret giving OCSC money since I later found out they're associated with the Rangers.