WASHINGTON (AP) — The Republican presidential nomination may be in his sights, yet Donald Trump has so far ignored vital preparations needed for a quick and effective transition to the general election. Trump's early campaign efforts — fueled in the primary season by the sheer force of his personality and free media coverage — have defied all who predicted they would fall short of what's required to win the nomination. The Republican front-runner's organizational disadvantage marks another warning sign for GOP officials who already feared he was unelectable this fall — even if he were well-prepared. [...] the Republican National Committee has been expanding its national footprint and accumulating detailed information about millions of general election voters since soon after the GOP's disastrous 2012 election. Trump has lashed out at other candidates for raising money from wealthy donors, but GOP leaders anticipate he will need to do the same thing in the coming months. Absent a massive personal investment, Trump and his party will be tasked with raising millions of dollars a day to match spending levels from the past election.