My gut feeling:  if Trump loses but throws one of his fits, there may not be much right-wing violence right away.  But watch out for the Tim McVeigh types.  Possibly with a delayed arrival.

If Trump wins, there will be immediate violence from the left-wing and lots of it.  But it would be targeted more on things than on people.  Doesn't make it it in any way right or good, but it would be a different beast.

We'll see.  Trump losing but then conceding honorably would likely stem most of the problems from the right-wing side, but I share that fear that he may be too much of a narcissist to do that.