I visited here last summer. It is located in Russellville TN. They don't have all original artifacts but the house was saved from destruction by local groups. It is well worth a visit. They have another small museum on the grounds. http://www.longstreetmuseum.com/
@Pete Longstreet if you can go mid-week, I was fortunate to have the Guide and place to myself for over an hour.
Really informative guide and was able to see some of the hidden goodies.....
When we were there we had a chance to talk to the guide also. They have living history events there. He sews uniforms for reenactors in the small building.