The Blood Mountain Shelter is a 2-room stone building with a wooden floor and fireplace. It was built by the Civilian Conservation Corps in the 1930's and is on the National Register of Historic Places.
Personally, I was amazed when I stood at the front door and thought about the human effort necessary to build it! Woudn't have slept in it for any amount of money, though.
If you haven't seen this anywhere else ... THERE IS NO WATER ON BLOOD MOUNTAIN.
Because of tremendous use by AppTrail through hikers, camping is restricted to specifically designated sites on the west/south approach to Blood Mountain. The Georgia AT club has created about a dozen well-made, level tent sites and separated them enough to allow some privacy. These are discussed on several AT websites and in AT guides.
If you're really adventurous, there are a couple of secluded tent sites near the summit, but you have to carry up all your water!
The official parking area is just north of walasi-yi on GA Hwy 19; there you can take a connector trail,the byron reece memorial trail, to the AT. there is practically no difference in distance walking from here instead of from walasi-yi. Or, if you really wanted to be enviro-friendly, dont drive up the mountain at all; hike from Amicalola Falls state park, the place where most thru-hikers either begin or end their hike on the AT. Its only about forty miles and usually takes only 3-4 days.