I don’t think Trump will get that many Dems nationwide in the General, but I can see him getting 40% of the Dem vote in WV. Democrats are so anti coal, West Virginians know the election of Hillary means the end of their economy and livelihoods.
But let's say he gets 20% combined with an about +60% increase in Rep voter turnout and -30% Dem turnout this cycle as indicated by a recent report then things are looking very good.