I think the only way Trump stays on as President after January 20th to launch a real, honest-to-goodness coup d'état, with soliders and armor on the streets, mass arrests of opposition figures and seizure of media outlets (including, at this point, Fox News; Murdoch has been wavering in his support, and we can't let that happen).
I doubt that will happen, as Trump probably too cowardly, the officers corps too professional and the regular servicepeople too loyal for any such extreme actions. It seem likely, however, there might be attacks or attempted attacks against election administration personnel and officials, as well as legislatures meeting to select the electors to send to Washington by deluded Trumpists think this will turn things around. If that were happen, I'm sure A&H will blame the glow niggers 100%, they dinnu nuffin',
I think more likely is that Trump will hold his own private inauguration, followed by setting up on Pretender administration.