If the Republican Party knows what is good for them, they'll keep Don Jr. shrink wrapped in the back of the warehouse, he's too unbalanced.
Trump did come close, but the election had a record turn out, which means there are currently more Democrat voters than Republican voters in the United States...this is not surprising though, urban centers always outnumber rural areas.
As for tariffs, now that your Party has inherited the white working class, it will be interesting to see which of these policies, if any, the next GOP candidate continues to implement to keep them happy(Economic nationalism, immigration, foreign policy)
The problem being of course, that white collar Republicans tend to hold complete opposite views on these issues than blue collar workers, so...I imagine the struggle within your party will continue.