I think I've seen a little discussion that the Trump candidacy will lead to/means the end of the Republican Party.
I disagree, based mainly on my memory of the 1964 election and its aftermath. First I'd like to say there's little evidence that 2016 will be as one-sided as 1964. While Goldwater was a more attractive personality than Trump, we forget how much LBJ was respected if not loved in 1964. He had rallied the nation after JFK's death and had accomplished things which seemed unlikely. So HRC is no LBJ.
After the landslide there was, IIRC, a lot of discussion that it was the end for the GOP, Areas which had never voted Democratic, like my upstate NY district, had gone for the Democratic candidate, not only for President but for Congress. That's how we got the super-majority in the Senate. Cointon is not going to beat Trump by upwards of 20 points; more to the point she's going to be very lucky if she even has a bare majority in the Senate and squeaks by the in House. So the Republicans would have a good base to rebuild from, much better than the 1965 Reps.
It's arguable that the divisions in the party are greater and more firmly based now. It may be true, though I'd bow to the political scientists on that. Certainly the divisions on free trade and immigration, and between social conservatives and populists seem sharp. But in the long run, the pursuit of power is a great consolidating force. So I'd predict the GOP would rebound rather quickly after a Trump defeat, just as it began to in 1966.