I have this writeup for anyone who asks about my favorite ride, which traverses the Santa Monica's. I will herewith paste:
It so happens my favorite ride is recorded on Strava (link below), and courses across 30 miles of the Santa Monica's. This covers a lot of the territory traversed by the original Mulholland Challenge route, going 97.7mi, with 8,747ft elevation gain. The ride as shown starts in Santa Monica, but you can park on the side of Topanga Cyn Rd near PCH, then pedal up Topanga Cyn Rd. Then...
-At the Topanga post office veer left onto Old Topanga Cyn Rd. Over the top to Mulholland Highway, and left.
The ride takes you 25 miles westerly on Mulholland Highway. You get a lot of mountain views; the farther west you go the less developed and wilder and more scenic it gets.
Then just before Mulholland descends to the sea, you veer off on Little Sycamore Cyn Rd. on the right, to stay up in the mountains. When Little Sycamore crosses the county line into Ventura, it turns into Yerba Buena Rd, and the road surface immedately takes a turn for the worse, with many cracks that will rattle your bike and you. Caution! When Yerba Buena descends, you will have a quite technical descent, with curves and the cracks in the road. This will test your cycling skills. I always look forward to this challenging part of the ride.
The second descent on Yerba takes you to the intersection of Cotharin. Right on Cotharin for grades that will beg for a 32 cassette. Cotharin eventually becomes a dirt road, but you veer to the right to continue on Sierra View, which becomes Deer Creek, many cyclists' favorite descent in the Santa Monca's. But first take in the view from the top of DC. This is as far west as you can get on these roads.
You end up on on PCH along a beautiful coastline. Head west, probably with a tail wind.
If you have "had it" at this point, stay on PCH till you get back to your car on Topanga. PCH is a hilly route, and you will have another 1000 feet of ascent to get back. If you are in for more:
Continue on PCH about 5 1/2 miles to Decker Cyn Rd, Hwy 23. Left up Decker. Some grades here will be reminiscent of Cotharin. After the fire staton at the top, do a right on Lechusa, which ends in short order at an elbow of Encinal Cyn Rd. Go straight on Encinal, which will be a boring descent, compared to what you've been on: Several miles at 6% grade. Or just take Decker back down for a spicier descent.
Back at PCH, continue west to Topanga and your car.
AMENITIES ALONG THE WAY, in order of the route:
In Topanga, a little store on the right. On Sundays it doesn't open till 10. There's also some little health food store with cookies on the left somewhere along there.
Water at community entrances, one along the first incline on Mulholland. A spigot outside the unoccupied guard shack. Or at the top of said incline, a occupied guard shack. Guard there always lets me use faucet.
Water and bathrooms at Strauss Ranch about 10 miles along. The first Strauss entrance is the parking lot. Take the second entrance to the white buildings, one of which is a bathroom and water faucet. Once past Strauss Ranch, you are on Rock Store Hill.
If you want food, then right near here is the Rustic Canyon Store & Grill. Shortly after Strauss, detour off Mulholland to the right on Sierra River Road. A quarter mile down the road is the store. Or a quarter mile up Mulholland is the Rock Store cafe. If you're not intimidated by the 200 or so motorcycllists hanging out, you can buy great 8" oatmeal cookies here.
Maybe 5 miles along at 33335 Mulholland there is a water faucet in the driveway.
On Yerba, at the bottom of the first descent there's the Circle X Ranch ranger station, easy to miss on the left. Bathroom & water.
Once on PCH, at the intersection of Yerba Buena, there's Neptune's Nest restaurant. They have a water keg in front for anyone to use. And porta potties, and you can order food to go if you can stand to wait in line.
If you take the option up Decker, then at the fire station at the top there's a water fountain in front, put there just for cyclists.
Back on PCH, there's a LA County fire station on the right, with a faucet at the driveway entrance. Maybe a mile past Decker.
At the intersection of Mulholland Hwy, there's Leo Carillo State Beach. The campground across the highway has bathrooms, water and a campground store. Turn left off PCH into the parking lot, and take the road back into the campground and nestled somewhere back there is the store.
Along PCH the beaches will have bathrooms and the larger beaches have snack bars open in the sunny season.
Across the highway from the south end of Zuma Beach there's a bicycle shop in the strip mall. Good for emergency supplies.
Right after Zuma there's an incline. For pizza, cut thru the gas station at the top of the hill, and there's a take-out pizza place in the shopping center on the right.
From here west, you are more in the heart of Malibu, and along here there's numerous stores around.
Across the intersection of Malibu Cyn Rd there's a park on with water and bathrooms and drink vending machines.
If you're doing the Tuna Canyon option (below), there's a faucet in a driveway on Stunt Rd, on the left about a quarter mile down. Put there by a kind homeowner for cyclists.
Here's the link to that Strava site I mentioned. It does NOT have the Tuna Cyn option.
Narly option: Tuna Canyon.
This is the most technical paved descent in the Santa Monica's that I know of. So technical, that there are stop signs where there's no intersection, put there just so motorists can get some comprehension of what they're getting into. Search on You Tube for "bicycle tuna canyon" for a virtual descent.
You can do this as an added 1400 ft of climb on the trip, or something to do on another day. To add this option:
In Topanga watch for Fernwood Pacific Dr. on the left. This will be a nice windy climb up a wooded residential area.
Eventually it crests and you continue until Fernwood becomes Tuna Canyon. Tuna eventually gets into this really narly, technical descent. Your rims will heat up from the braking.
This gets you back to PCH. Go right, pedal for just over 2 1/2 miles, then ascend Las Flores. Right on Rancho Pacifico and right on Schueren, then a sharp left to descend Stunt Rd to Mulholland Hwy. Left, and continue on the route. In 8 1/2 miles will be Strauss Ranch mentioned above.