You already have my citations! Sandburg, Burlingame (vol. 1, pp. 259-260) and, Elisabeth, you also had my original one from the Journal of the Illinois State Historical Society! I believe that Findley picked the wrong Thompkins.
Good sleuthing by all of us! Now, check out some related Spriggs trivia I will now post.
Joe
Before lodging at Mrs. Spriggs boarding house, where did the Lincolns live for a few days upon arriving in Washington City?
Also, since Mrs. Spriggs's establishment is no longer extant, what building now occupies the site? (I think this may have appeared before.)