I knew Chris would eventually show up and have details on the route through Linares - if anyone knows the area he does. Thanks Chris - maybe we will use that route to visit you one of these days - forewarning.
I got to thinking about this and started checking some new roads we know about on our recently updated Garmin 2757LM. I looked at several new roads we are aware of - periferico ring roads around towns - roads that did not exist a couple years ago. I found Garmin updates are pretty up-to-date.
Examples - we take route 90 south of Irapuato and Guanajuato through Penjamo and hook-up with 110 by La Piedad - then Yurecuaro - La Barca - Sahuayo - Jiquilpan - or we cut over to Chapala. Most of this route was completely rebuilt a couple years ago and there are several new ring roads around these towns. These were not on the map last year. The completed Arco Norte is on there. The new Devil's Backbone is on there. There is a diagonal new road west of Culiacan coming down 15D which I think was new last year and not on the map - now on there. Some of these roads show as thin lines for some reason so you have to zoom in close to see some of them. But they are there and on the new Garmins. There is a new ring road north of Jocotepec at the west end of Lake Chapala connecting 35 and 15 without going through town that is NOT on our Garmin. Every year new and better roads all over Mexico. I am sure Garmin probably has many more we are not aware of yet. Too bad Streets & Trips will no longer be issuing new versions - MS announced 2013 is the last version they will make. Still a good overall planing tool but over time it will be out of date. Doing Garmin updates at least once a year can be very useful. As we roam around this winter we may find more roads have been built.
This forum is probably the best source for learning about roads and routes as fellow travelers post what they learn.