The mountains of the Blue Ridge are tiny hills, to someone from Colorado or Oregon. Today, it's sometimes a challenge to see the Blue Ridge as a substantial barrier to transportation. The woods have been cleared, so there are no fallen trees forcing short detours or stumps in the trail knocking wagon wheels askew from their axles. Hikers find it easy to climb Old Rag and other Blue Ridge mountains in a day, just for exercise.

Of course, if you were bicycling on a road through one of the gaps in the Blue Ridge, you would feel the uphill climb - just as the horses pulling wagons felt it in the 1700's. Virginia was settled slowly by the English, and it took a century before they were at the base of the Blue Ridge. Governor Spottswood led the Knights of the Golden Horseshoe across the Blue Ridge in 1716, and his efforts to spur development and build an iron works in the Rappahannock River area led him to settle the Germans at Germanna - far from the nearest gap across the Blue Ridge.

In the 1730's-1750's, refugees from religious wars in Europe were able to enter the tolerant Quaker colony at Philadelphia, walk westward through the limestone valleys along modern-day US Route 30, and follow the Great Valley to enter Virginia from the north. Colonial settlers moved into Frederick and Augusta counties by walking up the Shenandoah Valley. ("Up the valley" is uphill, to the south - ignore your old prejudice that north is "up.")
Many Valley newspapers before the Civil War were printed in German, and land deeds were recorded in the language. There is even a deed in Swedish on the upper Potomac, reflecting the origin of one family. The Pennsylvania "Dutch" brought their German Reformed religion (Church of the Brethren, Amish/Mennonite, and Dunker), while the Scotch-Irish brought their Scotch Reformed Protestantism (Presbyterian).
Colonial settlers travelling from Pennsylvania into the Shenandoah Valley brought their religious and personal dislike of slavery. Slaves were common in the Valley, but the percentage of slaveholders and the number of slaves each controlled were far less than in Tidewater. Wheat and corn and cattle required far less labor than tobacco, and the social structure of the Valley before the American Revolution reflected the economy of the region.
The Anglican religion was the "established church" of the colony, and theoretically dissenters were tolerated but still required to pay parish taxes to the Anglican vestry. These taxes supported not only the social welfare functions of the parish (caring for widows and orphans, burying the indigent, etc.)
However, these taxes also paid for building Anglican churches and funding the salaries of Anglican ministers. In the Valley, however, the Anglican officials wisely compromised with the majority and avoided excessive building projects. Today, if you want to see brick colonial churches, be sure to look east of the Blue Ridge.
Most importantly, however, the immigrants who came through Pennsylvania sent their trade back the same way. To avoid hauling heavy farm products up the Blue Ridge, or trying to drive herds of livestock through the poor pastures in the mountains, the western Virginians took their business to Philadelphia and Baltimore.
The physical barrier, though unimpressive to the 200+ horsepower cars and trucks of this century, shaped the culture of the Valley. It was clearly different from Tidewater culture. When English settlers from Tidewater finally came through Ashby gap and Snickers gap, and established their farms on the eastern side of Frederick County, the differences were so clear that a new county (Clarke) was carved out of Frederick.