This is why I think the possibility of Trump suspending the Constitution and/or dissolving Congress isn't very far fetched.
Nothing is far fetched with him.
That's why I find it incredible when people laugh at the notion he may not willingly leave office should he lose.
There is no "leaving office" upon losing, though. The outgoing President doesn't "hand over" anything to his successor. The ceremony is a formality, the presence of the outgoing President a courtesy. Once the electoral votes are official (and there is little the GOP can do to that process as long as the Democrats control either the Senate or House) the rest is just time passing. At noon on January 20th, the President-elect legally becomes the President, and the former President is a regular citizen, with no more authority than you or me, no matter what he (or she) might claim.
Mr. Trump can refuse to move out of the White House, and he can try to issue orders but that is not "refusing to leave" it is
staging a coup. Might Mr. Trump and his immediate supporters try to stage a coup? I find it possible they'd considerate it, but they really are a pack of incompetent morons, so I doubt it would go well. If the entire Republican leadership rebels against the Constitution and tries a coup to seize power (something that is extremely believable, as they are doing so presently), I think the big determining factor is how the Democratic leadership responds... which is the thing that worries me most about possible futures.
Democrats, and establishment figures in general, are very reluctant to point out that the emperor is a naked moron leading a cult that is the 21st American equivalent to the Nazis. They continue to normalize the GOP, even when the Republicans and their orange leader are so far out of the ballpark that the captain on the cruise ship is assigning them rooms as they sail over the horizon. If the Republicans (or Mr. Trump and his crime family) attempt a coup, the President needs to immediately treat it as the treason it is and instruct their lawful subordinates to deal with it as swiftly as possible, using whatever force is necessary (subject to the laws of the United States and Geneva Conventions). Afterward, the perpetrators need to feel the full weight of the law - very long prison terms if possible.