I learned a long time back that if you need to go up Highway 1, avoid 92 like the plague unless you go really early (like before 8AM), otherwise it gets packed and it could take you 2h to just reach HMB. Thus, I came in from the north and promptly parked at the wrong trailhead (Grey Whale Cove) and started my ascent. I fortunately realized this within about 5m and headed back down to my car and drove another minute south to the proper trailhead "lot" (more like a pullout with space for 5 cars), which was full. Fortunately, there's another larger lot on the west side of Highway 1 a bit south; this was pretty empty at 8:50AM.
After a careful, but short, walk up Highway 1, the hike was on! The hike is mostly a fire road and about 8m round-trip. It's not overly steep but steep enough to feel :) I did some running bursts on the way up at times, but didn't want to blow my legs out given the length and unfamiliar territory. You get some really nice views on the way up and at the peak. Unfortunately, it was a bit fogged out on the ocean side on this day. Here's a pic at the peak:
It took me around 1:10 to reach peak and less to come back, though I was also jogging at times on the way down. If you were just hiking, it's probably be 2.5-3h depending on how fast you can go up steep hills :) This is not a good trail running hike though as the ground is pretty uneven and very hard - be careful if running. Also watch out for mountain bikers on the way back. There weren't many today but I read they sometimes come barreling down.
Overall, a good workout hike and some nice views to boot. While longer, the difficulty was close to Mission Peak, but without the ridiculous heat. Not as hard as Black Mountain. Finally, I'd recommend getting to the lot at least by 9:30AM on weekends - when I got back around 11, the lot was completely full.
[1] http://www.everytrail.com/guide/montara-mountain-mcnee-ranch-state-park
