Hwy 31 route question

I can't find 31 on my map. I do see 58 going from Linares back over to 57 through Iturbide. I think maybe Chris qtla9111 may chime in here as he lives near 85 south of Monterey and has probably taken this route. Assuming there is a reason to go to Linares? Most of us take the route on the cuotas which much faster and easier - as explained above.