Red tape and permits: the guides listed should direct you to what you need and if dogs are allowed etc. Most just need the $5 adventure pass from the parks service from any ranger station while a few are free. $30 gets you a year for ALL hikes in SoCal. A few of the peaks require you to fill out a no fee trip report at a ranger station. Basically so they know if there's extra cars at the trailheads someone is stuck up there. Whitney is a whole other deal.
Also if you do bring dogs, know what you're doing. They overheat and burn themselves out faster than you.
So you want to start hiking...
-Cowels mountain: pay no attention to the people zooming by you who look like this is their morning jog. Bring a headlamp and do it at night.
-Mount Woodson (aka Potato Chip Rock): Now you finally get to wait in line for the photo every freaking person in San Diego has on Facebook. Bring plenty of water. Go before the sun gets hot. Massive crowds though. Only worth it to say you did it.
-PCT by Mt Laguna: Breathtakingly gorgeous views of the desert floor from the cool air of 5000ft. Spend the drive here getting run off the road by motorcycle and sport car clubs. First hike without throngs of people so enjoy the solitude.
That seemed fun, what else is there?"
You've finally bought that REI membership and are getting really fucking annoying talking about your new hobby. These require more of a drive.
-Eagle Rock: The only hike to a named rock that doesn't require extreme squinting to see the animal. Detour through Julian on the way back for some motherf*cking apple pie.
-Tahquitz Peak: A nice little primer before you start hitting the major SOCAL peaks. Also a good beginner snow hike in winter.
-Santiago Peak: The OC's highest point. Great views of the ocean.....if there's no smog or clouds.
-Cucamonga Peak: Another in the "beginner guide to hiking mountains" series. Less crowds than Baldy.
-Bridge to Nowhere: Pros: not uphill, you get to hike in a creek. Cons: The canyon is crazy hot in summer.
-Nike Missile Site: Pros include a cool hike north of Santa Monica to an old Cold War surface to air missile base. Cons include traffic on the 805.
-Mt Baldy: The classic SOCAL must hike. Enjoy such lovely sights as "group of teenagers listening to shitty music on a speaker" or "dude who is wearing jeans and only brought a single 16 oz bottle of water." And last but not least "that 73 year old Asian woman who is moving way faster than everyone else." Be careful not to take the wrong trail down, you'll end up miles from your car. Better to go in late fall to avoid the crowds. Another good beginner winter hike. First of the three big peaks in Southern California.
These are best done in early spring or after a big rainstorm. Otherwise you get to look at dry, uninteresting rocks. Unless your a geologist that doesn't sound fun.
-Cedar Creek Falls : This hike had a reputation for loud, binge drinking idiots but its gotten slightly better since the parks service started policing it. Bring water, go when its cool and remember you have to hike back up on the return.
-Santa Anita Canyon: Easy hike in the San Gabriels. Can be crowded.
-Lewis Falls: Do some other hike around here too, this one is only a mile long.
The Desert Hikes
Enjoy the fresh desert air and a clean healthy hike. Or do hallucinogens like all the other damn hippies that come out here.
Go in winter. However much water you think you need, add a Liter to that. If you're thirsty, you're already dehydrated. That said these (especially Anza Borrego) are hidden gems.*
-Calcimite Mine The pictures don't do this justice, this is slot canyoning to rival anything in Utah. Some nice offroading if you have a Jeep too. The whole area is a web of canyons so if you trust your sense of direction you can explore a bit...or you get lost and die.
-Split Mountain and Wind Caves see more slot canyons, caves formed by wind alone and fossilized scallops. Cool hike.
-West Butte Borrego Mountain More awesome views and slot canyons.
anything in Joshua Tree NP: The whole park is beautiful and worth it if you're in the Palm Springs area. I'm not going to list anything here other than put it on your bucket list.
Trails? Where we are going, we won't need trails. (Easy off trail bushwhacking and light scrambling.)
-Mount Baldy via Iron Mountain traverse I want to emphasize this is a very hard hike that requires you to shuttle cars since you end the hike at a different trail head. This hike is only here for organizational purposes and should be done later.
"You know, I think I should plan a Mt Whitney trip later this year..."
-Badel-Powell This one probably should go in the intermediate section.
-San Bernadino Peak Another of the hidden gems that no one seems to do unless they're doing "the six pack." They are missing out, this one is worth it.
-San Gorgonio via Fish Creek Most people do the harder route up vivian creek (don't worry that's later). But this one has you go by a crashed WWII aircraft.
-Backpacking in San Gorgonio A good primer to sleeping in the woods. This is a 2 day trip.
-San Jacinto via the Tram John Muir himself called this one of the best views. But you're a wuss and get to take a Swiss engineered tram car most of the way. If you're on a Mt Whitney training workup, enjoy the easy hike. It only gets worse.
The Hard Ones
Blisters, and a bit of self flagellation. They're also pretty much mandatory if you want to get up Whitney in a day so....
-San Gorgonio via Vivian Creek A glute burning, steep climb. "Its around the same altitude gain as the Whitney trail," is something you can say to console yourself. But try not to remember Whitney is 4 miles longer and has less oxygen.
-Cactus to Clouds. 10400 feet of altitude gain in 23 miles. And you're going uphill for 3/4ths of it. Rated one of the hardest day hikes in the US. Should only be done in winter or veeeery early spring. On the plus side, you're supposed to buy a pass to take the tram down, but they've never asked.
-Mount Whitney Highest point in the lower 48 and all around breathtaking hike. You should get there a day early, maybe acclimatize at a hike by Mount Langley or to Lone Pine Lake. Or you can do what I did and just drive up from San Diego after work, get to the trail head at 10:30pm, and not sleep at all, and then start hiking at midnight.
Don't do what I did.
-The 9 Peak Challenge The only one I've not done on the list but it seems cool so I'll put it on the board.
Edit: if there's enough of a demand I have a half written gear guide about what you should need to get started.