Highway Urapuato, Penjamo and La Piedad?

[NanN]

Does anyone know if the highway that runs from Urapuato to MEX 15 through Penjamo and La Piedad is really slow going or does traffic flow pretty well? I have driven many two lane, secondary highways in Mexico and some are great and some are just a pothole infested, twisty-turny, nightmare plagued by little villages with three topes each every 5 km.

I am heading down to Ajijic for a few days and my options are to go this route above or stay on the toll road through Moroleon and connect with MEX 15 just above Morelia. I drove that "gotta love it all autopista" route in May and it was great but I rather thought the other might be nice too if the road is decent, as going or coming back that way, we could check out the ruin near Penjamo.