Huck falls asleep holding the gun and is woken by his father; he lies and says he was guarding against a robber in the night.
Pap, in the midst of one extraordinary hangover, doesn't remember the night before anyway, so it's all good.
Outside, Huck sees the river rising and knows it's June. He implies that he's starting to miss town.
As luck would have it, he finds a drift-canoe coming down the river (that is, a canoe with no one in it, for those of you who don't speak Huck).
He hides it away for later.
Back at home, Pap gathers up some lumber and takes it to town to sell for money (read: whiskey). While he's gone, Huck gathers up supplies and leaves through the hole he sawed in the back of the cabin.
Then he does what every normal boy dreams about at least once in his childhood: he fakes his own death.
He beats down the door to the cabin and spreads pig's blood everywhere to make the cabin look like a robbery/murder-scene.
Then it's into the canoe and out on the river in the pitch black darkness.
In the nail-biting scene that follows, Huck has to lie down still in his canoe as his father paddles by right next to him.
Because of the darkness and also possibly his stupidity, Pap is oblivious to the empty canoe less than six inches from his path.
Once he is out of danger's way, Huck chills out in his canoe, smokes a pipe, looks at the stars, and eavesdrops on the nearby ferry full of men. It's all very picturesque and beautiful.
He then paddles out to the uninhabited Jackson's Island, an all-inclusive resort destination in the middle of the river.