Mt. Stone is the highpoint of Mason County, and requires over a mile of elevation gain to reach the summit.
Starting at the Putvin Trailhead, you'll find a smooth trail that quickly picks up in steepness and eventually funnels you through a short section of 3rd class scrambling before spitting you out at the (unimpressive) Lake of the False Prophet. Now, you've entered the Olympic National Park, and several route variations are possible, the fastest of which involves staying low to reach the (impressive) Lake of the Angels, then crossing its flow and following the moderately defined trail all the way up to the summit.
To reach the top, you'll contend with a short and fun scrambling section where the trail is well defined and rock is quite solid (by Olympic standards), and you'll be rewarded with a wide view into the core of the Olympic National Park, including the great Mt. Olympus.
More details on the route can be found here, on Summitpost: https://www.summitpost.org/mount-stone/151845
The gpx line here shows two potential routes (going to Lake of the Angels or going more directly up) but runners can take any route up or down for the FKT.
That looks like fun! Planning to go for it this evening.