IT'S A SURE BET that Mark Twain's "The Adventures of Huckleberry Finn," published in 1885, is in line for the title of the Great American Novel. So it was only a matter of time (100 years, to be exact) before someone turned the classic into the All-American musical.

The show that finally filled the bill is "Big River," an amiable amble through Twain's tale that's not only hummable but also remains remarkably faithful in the telling. "Big River," which visits the Kennedy Center Opera House with original star Ron Richardson, opened a year ago this date on Broadway, where it won seven Tony Awards.

Through Roger Miller's songs and William Hauptman's book, "Big River" spins the familiar story of Tom Sawyer's pal Huck Finn (Brian Lane Green), who escapes from his drunkard father and confining Missouri hometown and sets off for adventure on his own. On the Mississippi, he is reunited with Jim, a runaway slave, and he vows to help Jim to freedom, friendship eventually overcoming his ingrained attitudes toward blacks.

Aboard their cozy raft, Jim predicts "considerable trouble and considerable joy" for Huck, and sure enough, they fall in with a variety of saints and scamps. But plucky Huck trusts to Providence (it also helps that he's a good liar) and gets himself and Jim in and out of a passel of amusing scrapes.

All the performers are fine, but the show really livens up when Richardson, as Jim, liberates his electrifying voice to sing Miller's rousing "Muddy Water." This is country singer/songwriter Miller's first-ever musical (he says he had only seen one before "Big River"), which may explain the freshness and exuberance of his flavorful score. Spiced with country, gospel, blues and Dixieland jazz, it more than once transforms the plush theater into the Grand Ol' Opera House.

Director Des McAnuff shapes the story into high melodrama, sets Huck's reedy narration at a gallop, and bedecks the staging with all sorts of dandy details, including a clever mobile raft. Heidi Landesman's lovely set is pure Americana, dominated, as is Twain's book, by the mighty Mississippi, here a luminous ribbon of light that reflects the rapidly shifting moods of "Big River." BIG RIVER -- At the Kennedy Center Opera House through May 24.