There was a rash of Elvis sightings in the late 70's and early 80's, but there was a catch. People were picking up a young man dressed in a military uniform a few miles away from Graceland and he would ask to be taken there. People thought he was a soldier on leave trying to do some sightseeing, but he would tell people his name was Elvis Presley. Of course, they wouldn't believe him, but according to some of the stories, they would start to believe when he disappeared out of their cars as they approached Graceland. Some said he would walk through the gates and one truck driver said he sang to him as he drove.
Are these stories true? I'd like to think so. There have been way too many stories about Elvis haunting Graceland for them all to be made up. As far as the hitch hiking Elvis, only the drivers know for sure.
From Marc Cohn's song "Walking in Memphis"
Saw the ghost of Elvis
On Union Avenue
Followed him up to the gates of Graceland
Then I watched him walk right through
Now security they did not see him
They just hovered 'round his tomb
But there's a pretty little thing
Waiting for the King
Down in the Jungle Room.