Total Oblivion, More or Less by Alan Deniro

Booklist starred review:

For 16-year-old Macy, the whole world has gone crazy, quite literally. Barbarians from antiquity have invaded America, while bizarre plagues and impossibly shifting landscapes ravage her Minnesota homeland. Together with her parents, sister, brother, and a possibly evil dog, Macy sets out down the Mississippi on an adventure that takes her into the smoldering ruins of St. Louis, aboard a wooden submarine that’s bigger on the inside than outside, and finally into the stone-skyscraper capital of Nueva Roma. All the while she dodges oil-men turned slavers, plague-instigating wasps, an albino bounty hunter, and, perhaps most dangerous of all, her scheming younger brother. DeNiro (who flaunted a knack for offhand sf oddness in Skinny Dipping in the Lake of the Dead, 2006) makes sure never to do anything as dull as explaining what the heck is going on—we simply accept that the world has become a surreal, historical landscape come to life and move on. He drops in so many tantalizingly inspired touches—the new (old?) empire considers Post-it notes a precious natural resource—that leaving his inside-out America at the end is almost painful. There aren’t many writers who take weirdness as seriously as DeNiro does, and fewer still who can extract so much grounded emotion, gut-dropping humor, and rousing adventure from it. A dizzying display of often brilliant, always strange, and definitely unique storytelling.