Linda, By northern route, do you mean U.S. Highway 2 along the edge of Glacier National Park? THAT'S the NORTHERN ROUTE!
That's the route I took on the way back from my big Western trip in '89. >From Portland, OR, to Coeur d' Alene, ID, to Kalispell (with time off for touring the park), then through the 5200' Maria's pass along the south edge of the park. From the east edge of GNP, it's all flatland till you get to the Appalachian range in eastern Ohio. For the best tourist view, I went through Maria's Pass at 7500' just after dawn when the air was very smooth and nice. Before entering the mountains, I made sure I was already up at 7500' over the flatlands in the Flathead valley near Kalispell. That way I didn't have to worry about whether my climb ability was enough to meet the rising ground in a narrow mountain valley. Ed
