The first thing you need to do is to disregard the opinions
of the nay-sayers who are blowing smoke on a topic they have no actual experience with, and look for information from people with verifiable actual experience. I have a 2013 Chev 3500HD that has travelled to Puerto Vallarta every year since it was new. That's SEVEN trips to PV and back, and I have had ZERO fuel-related issues. I haul a 5th there and back, and I use my truck as a daily driver for the 5 months I spend there each year. Certainly there are a few little things you need to do to avoid problems, the most important of which is to make sure your truck gets up to full operating temperature each time you drive it, and also don't let it sit and idle for any length of time. Letting it sit and idle for a lengthy time will bring on the Check Engine light even back in the US or Canada using ULSD. Also don't believe the nay-sayers who spout their opinions
that ULSD is not available anywhere but at the border. I have a Pemex Delivery Report all the way back in 2017 showing ULSD being delivered to stations in PV and my friend who provided this to me assures me that nothing has changed since then. Opinions are worthless, actual experience is what you need to look for.