The history of access to Yosemite Valley is interesting – highways 120, 140, and 41 have not always been there. One of the first paved roads into the Valley was the original Big Oak Flat Road (a history can be found here). It was a dangerous road and was eventually replaced with the safer tunnel design of the current road, and then eventually taken out via a major rockslide in the 1940s. Today this road is an afterthought, a forgotten footpath frequently blocked by rockslides and overgrown trees.
This road is quite visible from many points in the Valley. As you descend 41 from the Tunnel View, look across the valley at the slopes west of El Capitan. You’ll clearly see an old road cut through the terrain. It disappears in places (where it has been taken out by rockslides) but it’s easy to visually pick it out.