It is also at the junction of Interstate 5 and SR44 that heads east to Lassen and Susanville. Real handy for those heading to and from Eureka on 299 or for those who wish to head NE to Alturas and Modoc County.
While I know nothing as well about Supercharger approval, Tesla does try to find locations where there is no or minimal rent. There have been suggestions that lately many retail establishments want Superchargers because of increased traffic and sales, so Tesla is not charged rent for the spaces and infrastructure. Municipal situations are different, however, since there won't be any increased revenue to businesses.