I doubt the protests against HRC's victory in the state legislatures when the EC voted would have been anywhere near as severe as they actually were. Trump would have called the system rigged and likely not acknowledged his loss for days. He would also press for recounts wherever they might reasonably be possible. Basically, he would act as the Dems actually did, except he, unlike HRC, would have been the voice of even the nuttiest conspiracy theorists. Trump does not accept defeat with grace.
This. Trump would have been abandoned by most in the party establishment after refusing to accept the result, only having conspiracy shows as his support base, while the current effort to delegitimize Trump is a party wide effort lead by the Democratic establishment and the practically the entire media.