I suspect bribes would work. For $1M or $10M each, you could get enough faithless electors. However, I also suspect the Congress would vote (by state, and the GOP has 30 states) for President Trump.
That is only if it gets to a vote in Congress. It is quite possible that the people in flyover country would react adversely to the attempted coup, without waiting for a vote in Congress, and it will be wintertime. I hope and pray that the other side will back off before they have to be reminded where governments derive their just powers.
Those in red states don't even have to do much shooting; just (as mentioned in this commentary) cut off supplies to the cities. #BlackThugsMatter blocked highways for three hours with mobs and linked arms. What happens if farmers block the highways with nearly worn out farm vehicles parked sideways, or side by side, and mechanically disabled (perhaps even with concrete poured to cement them in place)? Whatever heavy equipment could move those tractors would (1) have trouble getting there through the traffic, and (2) be operated in most cases by deplorables. By the time the farm vehicles were cleared, there would be thousands of abandoned cars sustaining the roadblock, probably with more disabled tractors in the middle of that roadblock. Nope. The thug class does not want to start down that road if they have any sense - If!
For those that believe electricity comes from a wall outlet, and steaks were cultured in styrofoam packaging, please consider the immediate impacts if you choose poorly . . .
Loose the electric==>no water on tap--no dispensing motor fuel--no furnace for heat--no electric range for cooking.
Loose the highway and rail access==>no additional supplies--no motor fuel--no transportation--no easy exit.
Within two days of the disruption, totalitarian gang warfare for control of any remaining resources erupts. Police, fire, medical services are exhausted in the attempt to cope. Firestorms created by frustrated looters turning toward riot in an urban setting, mimics 9-11 on a wider scale, destroying the familiar outlines. Thirst and hunger deprive the survivors of the remaining dregs of self control. You will receive appraising looks from clusters of the starving. If you survive, you live with these memories flickering behind your eyes, for the rest of your days.
A little tune to further enlighten . . .
https://www.youtube.com/watch?v=3cQNkIrg-Tk