Broadway in many cities across the country are main thoroughfares thru downtowns with no suffix such aas Avenue, Blvd, Street, etc. Broadway is simply Broadway. But in Salem, it is called Broadway Street. It is a main thoroughfare, but the street name ends before hitting downtown Salem. It also stops short of Keizer. In Downtown Salem it becomes High Street, and at the Keizer border it becomes River Road.
At one time the Oregon Electric Railway ran down Broadway St between the Railroad crossing near Madison Street and went into downtown Salem along High Street. This was the passenger Interurban line. The freight Interurban line still exists along Front Street, but the electric operation stop decades ago. You could board an Electric train at Highland to head to Portland or Eugene. Salem's station was at State and High Streets. The Oregon Building was built by the OE.
The cache is about one block from Salem's not so common Broadway Street, yet behind a very Common Broadway place. The difficulty rating on Sundays would be higher as this area is quite busy then.