To answer your question a person would needs to know where you are going in Mexico. ULSD is not available in all areas of Mexico. I am familiar with Baja Mexico. ULSD is only available in Baja Norte. Baja Sur, which is Gurrero Negro South to Cabo, is LSD. As I winter in Baja Sur I have a 50gal spare tank in my toad, which gets me back to Baja Norte.
Others will need to talk about the Mainland. There are many internet post about Mexico Diesel.
2008 Bounder 38V DP
2004 Ford Sport Trac