Did the Beatles ever go to Graceland?
No, they only met that time in California. In the “Extras” DVD for the Beatles ‘Anthology’, Paul, George and Ringo mention Elvis. One of them (either Paul or Ringo) ask if any of them ever met Elvis again, and George tells a story about seeing him backstage at Madison Square Garden, probably around 1970-1971. That would seem to be the only time any of them saw him in person again. As to Lennon having a secret meeting with Elvis while in Germany, I believe Elvis was there before the Beatles were famous, so why some unknown British musician would ‘sneak around’ to meet the King is odd. I don’t believe it happened.