Mt. Mitchell is not that bad. The climb to the top off of the parkway is pretty tough and the climb to the parkway itself. But once you are on the parkway I'd guess it's only 4% at best and you even have some flat and down hill sections. But some of those climbs in VA and NC that goe up to the Blue Ridge Parkway are evil! they may not be HC but they are like 3-5 miles and 2500-3000ft of 10-12% average.