Like I said I am a great fan of Mark Twain, but as I look back again I read that section as even more off the mark:
....and the presence of a deep content and unbroken satisfaction in that hundred million years of holiday which I look back upon with a tender longing and with a grateful desire to resume, when the opportunity comes
You don't read that as implying both (1) some kind of awareness and contentedness while being dead, and (2) the desire to resume that experience (of death) later when he dies?
While it's clear that Epicurus doesn't hold there to be any pain in death, nor is there any kind of pleasure whatsoever in death, and death is not a thing to be welcomed, except when one faces pain for which there is no other remedy.
Do you see that differently?
I agree that there is some echoing of taking a devil-may-care attitude toward death that is consistent with Epicurus, but doesn't this cross a line and imply or in fact flatly express that death should flatly be viewed as a desirable experience?
"....when the opportunity comes"?