CHARLOTTE, N.C. — On Tuesday morning outside the NASCAR Hall of Fame, a small clutch of reporters and cameras gathered around a bus wrapped in Republican National Convention logos and listened as organizers kicked off a three-day, six-city tour across the Carolinas. A year from now, 15,000 reporters, columnists, camera operators and other media representatives will be swarming uptown as the 2020 RNC prepares for its finale: an acceptance speech by President Donald Trump as the party’s nominee for the fall election.