I went in via Rocky Branch from RT 16 a couple of years ago to Davis Path then visited the summit and then continued onwards down in the Dry River via the westerly Isolation trail. A serious blowdown from several year ago was cleaned up nicely but the last 1/2 mile or so before the Dry River trail where the trail transitions from a ridge to the sides of the drainage was quite challenging. The trail at one point appears to have been cut along the top of steep slopes and possibly cut into slopes, there were numerous washouts or varying width which required tedious navigating up and down loose gravel slopes. Its starts out easy and gets harder as the junction of the Dry River Trail is approached. We lost the trail bed of the Isolation Trail down near the junction with the DRT but quickly found the DRT. The DRT has similar washouts with various workarounds somewhat established until the suspension bridge. It was a long day.
I would vote for the Rocky Branch trail from RT 16 in and out.
I also did the lower Rocky Branch trail a few years back. It is an interesting hike with relocations in place for most of the washouts but there is one stretch where there was a change in the course of the river which required some route finding. I would be interested to see that area as the slides were a work in progress and expect it looks differently after a few seasons.