The park is very easy to find, just off Malibu Canyon Road (accessible via both PCH and the 101). Parking is $12.00 per car for day use, and I was delighted to discover that they have a couple of electric vehicle chargers. (Note: There is somewhere to park for free outside of the park, although it makes for a longer hike. You can find the info online.) The M*A*S*H hike, without taking any of the numerous side trails, is approximately 5 miles round trip.
The only difficulty I found was that there are several parking lots there, which I was previously unaware of. I parked in the first one I found and therefore had difficulty finding the trailhead, which was near the (I believe) fourth parking lot. Once we figured this out, we were on our way.
I was surprised to discover that Malibu Creek actually had some running water:
The views on this trail are absolutely stunning. We had perfect weather.
Much of the trail is shaded:
More stunning views. The trail does have some elevation, but only in one part (about midway, I'd guess) and it was a pretty gradual slope.
There are numerous side trails. Some have elevation/views. Some don't. We took only one of them, to the dam-created Century Lake:
We also got some Fall color, a rarity in SoCal:
The trail gets continually narrower until you suddenly find yourself at the site. While much of the show was filmed at the studio, some of it was filmed here:
On our way back, we stopped on a small bridge to enjoy the beauty and the quiet:
This was a truly fantastic hike. I enjoyed it thoroughly and have every intention of returning more than once. I recommend it both to people who live in the LA area and those who are visiting. You shouldn't miss it!