At the end, did MTL have a sense of vindication

[RJNorton]

Anyway, my understanding is that MTL returned to Washington

You are correct, Toia. According to Lincoln-Day-By Day she returned to Washington on April 1. However, she departed Washington to go back on April 5 (leaving Washington at 11:00 A.M.) accompanied by Senator Sumner, Senator Harlan and family, Mrs. Keckly, and Marquis de Chambrun. She stayed until April 8 at 11:00 P.M. when the Presidential party departed City Point for the return trip to Washington. Still absolutely no mention of Stackpole on Mary's second trip!

All we have on this is Herndon's handwritten notes from an interview with Ward Hill Lamon. I do wonder if either Herndon or Lamon were confused...perhaps putting (creating?) words in Stackpole's mouth?