I just completed this loop as a dayhike, and I should note that the route drawn on here and the distance do not correspond exactly to what I found. The drawn route seems to cut off a large portion of Rattlesnake Ridge, including most of the switchbacks. My Garmin had the distance at about 18.8 miles total.

That being said, I thoroughly enjoyed this hike. It was quite diverse - from walking along the ocean to going through ferns to being high above it all on the ridge - and extremely beautiful. The first four miles and the last ~2 are on the "road", so they aren't particularly exciting and generally lack views. Rattlesnake Ridge was quite overgrown with ferns and other plants, and higher up, there were a lot of overhanging branches that dumped tons of pollen at the slightest movement. That portion of the trail was definitely the hardest (having basically all of the elevation gain).

I don't know what the water level is typically like in the streams, but crossing wasn't terribly difficult. I had to do some searching for the right rocks to hop across (so as not to take my boots off multiple times in a short span), but that didn't take too long.

I got quite warm on the ascent. Not all of it is shaded, and it's strenuous. The views at the top are absolutely worth it, though! Plus, there was a nice breeze up there.

Overall, I thought this was a great loop, fitting exactly what I was looking for in terms of difficulty and distance. I was back to my car in 7 hours, so it's definitely a manageable hike for a day. If you'd rather enjoy the scenery a bit more and not push the pace, I could see this being a nice place for an overnight stay, too.