29 Pages -- Direct route to Guadalajara and Puerto Vallarta from Reynosa (Mission, TX) via San Luis Potosí. The other route is through Zacatecas and Aguascalientes. I believe this to be easier driving.
You can breeze through to Guadalajara, Lake Chapala, Ajijic in 1 1/2 days. Take the Maacrolibramiento that completely skirts Guadalajara and you'll be in Puerto Vallarta at the end of a hard day. Or take your time and enjoy!
The mining ghost town of Real de Catorce is well worth a visit. Just past Guadalajara are Tequila and wooded mountains. There is a hot spring just north of the city.