Iowa: Houseboat the Mississippi
Credit: Zuma / Alamy

To escape summer's humidity, Iowans head to their version of an ocean: the Mississippi. In McGregor, rent a houseboat – picture a floating camper – pack a cooler and rod, and then kick back with a brew while reeling in catfish. Pass 600-foot bluffs as you drift upriver to Marquette's Lady Luck riverboat casino. Hike among 14 miles of trails at Effigy Mounds National Monument. Or just dock at a small-town bankside watering hole for as much beer and local color as you can handle.

Getting there: From Cedar Rapids, drive 100 miles to McGregor and rent one of four houseboats at Boatels from $250 per day.