Very nice area. The streams are beautiful and the trails are well marked. After a heavy rain the previous day, the trail was muddy and very slippery in many places. The temp was in the upper 40's---perfect for hiking.
I found the petroglyphs disappointing, as they are generally fairly faint, and overwhelmed by graffitti from the late 1800's and early 1900's.
I'd suggest going when you are most likely to be the only person in the reserve. Man-made noise in the wilds is pollution as far as I am concerned, and the nature of the reserve trails puts you within ear-shot of other hikers much of the time, even if they are on the other side of, or in, the ravine. I was the only person in the Reserve initially (mid-week, mid-day, schools in session)---very peaceful. But, I heard two other hikers down in the ravine as I hiked the ridgeline trail out.
Also, I arrived from the north on Piney Creek Road heading south. Be warned, the road is gravel and essentially one and a half lanes wide. There is one VERY steep and long up-hill section of road on the way. I was driving a small pickup truck with nothing in the bed, so rear wheel traction was not great to start with. I made it, but was spinning my tires and shooting out gravel by the time I reached the crest of the road. I would not try this with any ice or snow unless I had a four-wheel drive vehicle. The approach from the south may be better (or worse!!).