This is from the 1985 Tony Awards, when Big River won Best Musical. It's a medley of two of the better songs, "Muddy Water" and "River in the Rain," both song by Daniel Jenkins as Huck, and Ron Richardson as Jim. I always liked the staging of the river and how they blended the raft into it, and you'll get a sense of that here.
Worth noting is that the company joins them for a reprise at the end, and as the camera pans, you'll be able to spot newcomer John Goodman, as he's starting his career. It comes at the 4:21 mark -- you'll see an actor playing Mark Twain, dressed all in his white panama suit, and three people to his left (your right) is Goodman.
But let's head down to the waterfront as Huck and Jim have to rush to get away...