Did Surratt and Slater know about Harney's Mission?

[RJNorton]

Thanks, John. Mary Surratt also asked the pickets guarding the road to Surrattsville how late they would be staying that night. Doesn't this indicate she knew the boat would not really be needed that night? (In other words she knew Booth's intended route.) Thus, I would think the boat was only for the kidnapping plan (yes, I realize you feel it didn't ever exist), and not the assassination plan. Thus, I am thinking Mary just wanted Smoot out of her house and lied to him about the boat in an effort to "hurry him on his way."