It would be interesting to describe this
alternate Samuel Clemens.

Does he have no major PODs before
the U.S. Civil War?

Does he and his brother still form a
short lived Confederate unit in
northern Missouri, and then move
west to Virginia City Nevada near the
start of the U.S. Civil War, when his
brother gets appointed to be a
secretary to the Territorial governor
of Nevada at that time?

Does Abraham Lincoln still become the
governor of Oregon Territory in 1850
when he is appointed by Zachary Taylor
to the position and die of old age there in
1892?