David,
    And thanks for the Day-by-Day information. Let me state the obvious
(something I have mastered to a fine art): That's quite a literary
mountain you've chosen to climb! I have the Poe day-by-day volume, and
it is invaluable. That was an impressive undertaking, but, even so, old
Eddie never got to be old Eddie. He departed this globe at 40. With
Twain, you get, oh, 34 more incredibly crowded years. Best of luck,
because we all stand to be the beneficiaries of your blood, sweat and
eye strain.
     Dickens met Poe in Philadelphia in 1842, during the first of Boz's
two American visits. Intriguingly, if Dickens had lived just two more
years, he undoubtedly would have met Twain, who visited England in 1872.
I don't have the date (I bet you do), but it was during this trip Twain
supposedly visited Dickens' grave in Poets Corner. I suppose that the
best meeting we get is when Boz's son and namesake, Charles Jr., stayed
with Twain and his family at the Hartford house while on an 1887 reading
tour.

Best,
Mark