Today, I came across an old highway that later became Aurora Avenue (no its not US 99 if that's what you're thinking) which apparently ran through Seattle west of the then-US 99/SR 1 (which took the route of WA 527 and WA 522 at the time). It was called the North Trunk Road and ran along Westlake Avenue N, Freemont Avenue N, N 50th Street, Phinney Avenue N, Greenwood Avenue N, N 85th Street, Aurora Avenue N and eventually split off from Aurora for a short period of time somewhere in present day Shoreline. A section of the original brick road apparently suffices at N 175th Street and Aurora Avenue N in Shoreline (part of which is now Donald Place N). The North Trunk Road eventually "died" when it was straightened out into Aurora Avenue and made into US 99/PSH 1. On a related note, does anyone know where I might be able to find more information on the North Trunk Road?
I live in U District, but I'll have to bike over there sometime and check out that route.