This is one of the most challenging hikes I've done in San Diego. They way up is very steep and there aren't any switchbacks. This is a hot hike, as there is no shade, so best to do it on a cool day and start early.
Start just outside of a gated community and head up a utility road to a powerline tower. From there, go right along the golf course, and then the real up begins! The trail is easy to follow and you can see where you are headed most of the way.
There is a bit of a break from the steep up at the saddle, then a little bit of downhill before the last stretch up San Miguel. If you're looking for a difficult hike, this is it! If it were longer, it'd probably be on par with El Cajon Mt.
Make sure you take plenty of water! I drank the 2 liters I brought and wished I had more. Also, be careful on the way down as it is steep and slippery with loose rocks. I slipped twice before I learned to take it slow.