I have camped in that area several times and this is how I would do it the first time: I would park in the overnight lot at Grayson Highlands State Park and start the hike at Massie Gap. The Appalachian Trail can be reached after about 1/4 mile up a steep hill. Follow the AT towards Rhododendron Gap, you will reach this place after a total hike from Massie Gap of about 2 miles. You will know when you get there since there is a huge "intersection" of trails, one of them equestrian, and it's a pretty torn up mess of dirt and rocks. There are signs in the area, one of them says "Lewis Fork Wilderness".  Keep following the AT from this place and you will enter a rhododendron tunnel about 100 yds or so long. Once out of that there will be campsites starting on the left of the trail, grassy areas with fire rings. There are many spruce trees around these camping areas that can help screen out heavy wind and the ever-changing weather of the area. Water can be found near these camps if you walk out of the campsite on the side opposite the AT through some trees into a clearing with a great view into NC. You must keep walking just a little down the hill and there is an area with a spring. Hard to tell you the location without knowing which camp you may choose but it is there and I don't think marked on the AT trail maps. The sure fire easy water to find is behind the Thomas Knob Shelter following the blue-blazed trail but that is another 1 mile from the camping area I described. The shelter always attracts a large crowd and will most likely be taken on a weekend anyway so never count on occupying it. Hope this helps.