Easy Routes Through the Appalachians?

groundhogy wrote:
What are the least mountainous routes if you wanted to cross?

You're not giving us much to go on. with no start point or end point. But I'll give my opinion. Assuming you are either in eastern PA or trying to get there.
I-81 if you are going north to south/south to north. It hits the gaps in southern Virginia. So you really don't "go over" the mountains.
I-76 if you are going due east or west.