At this time of year, many people plan to take time to hike into the upper reaches of the mountain streams to camp and fish the sulphur hatch for several days. If you choose your campsite carefully you can fish three different branches for three days and get great fishing on all of them. Just pace yourself carefully so you are fishing each branch until dark. I do well with the Shenk's Sulphur Dry size 16 & 18 and Murray's Sulphur Dry size 16 & 18.
I have been doing well with the Murray's Rapidan Dry size 14 & 16 and Spirits of Pittsford Mill size 16 in addition to the Sulphur patterns above all on a 6X Classic Leader.
The recent rains have provided some excellent water conditions for these streams. Just make sure that you do not spook the fish and that you do not get behind someone. My book Trout Fishing in the Shenandoah National Park covers the access to the streams in the Park.