Washington — Defying his reputation as a 1950s square, the new, more casual Mitt Romney is popping up around the country as he readies a second run for president. He's going tieless on network TV, strolling NASCAR pits in Daytona and sporting skinny Gap jeans bought for him by his wife. His latest campaign book, just out in paperback, opens with a regular-guy scene: wealthy Mitt in a Wal-Mart checkout line, buying gifts for his grandsons and comparing the surroundings to Target, another discount store he says he's familiar with.