I think two of the PBS adaptations from the 1980s are exceptionally good:
"The Mysterious Stranger" and "A Private History of a Campaign That Failed."
In each case, what sets them apart for me is the way they combined more than
one element.
  I thought the use of scenes from Twain's own days as an apprentice printer
to frame the Stranger was outstanding. Besides the obvious echo of "The
Wizard of Oz," it allowed for a great conclusion. After 44 advises the
narrator to "dream other dreams, and better," we see young Sam Clemens
sitting on the banks of the Mississippi, watching a steamboat drift by.
Better dreams, indeed!
  The Campaign That Failed was quite good from the start, but I particularly
liked the way "The War Prayer" was tacked on at the end. To me, the
implication was that the stranger who "translated" the war prayer was one of
those kids from the Civil War. And, since really both of them are Mark
Twain, it works very well.

Bob G.