HANOVERTON, Ohio — GOP front-runner Donald Trump tried to prove over the weekend that no perceived misstep can derail his march to the Republican presidential nomination.Trump enjoyed a relatively controversy free multi-state tour Sunday ahead of primaries that could determine whether he wins the GOP nomination without a contested summer convention.Perhaps most critical to that equation is Tuesday's winner-take-all contest in Ohio, where the real estate mogul and the popular governor, John Kasich, have intensified their focus on one another — Trump calling his rival "a baby" and Kasich suggesting Trump and the violence at some of his rallies represent a "dark side" of American society.Besides Ohio, candidates are readying their closing arguments in Illinois, Missouri, North Carolina and Florida, with the total number of delegates at stake Tuesday accounting for more than a quarter of the 1,237 necessary for nomination.Texas Sen.