Thanks to all for the info. provided.
I have GPS with the latest maps, I use Microsoft Streets and trips 2013 for route planning (not while driving.. my navigator is not computer literate) and I have the SCT maps saved on my laptop. All give usable information but things like tight curves, multiple topes and low bridges are not shown. I also like to preview my route on Google Maps and zoom in on contentious interchanges etc. GM seems to have the latest updates of them all.
I have a tentative route plotted re GM around Guadalajara to get to Villa Corona so will have to see how that plays out.
Again, thanks to all for the info.
Scorp.