There are a number of other ULSD spec'd vehicles that run on crap diesel just fine. The regen cycles a bit more, but that's it. A number of Sprinter folks with ad-blue systems have run on non-ULSD diesel for short periods of time (a couple tanks) without issue. I've seen a number of NCV3's doing long runs down through South America without issue, but it've never inquired about how they do it.
As of now, I haven't read about someone braving non-ULSD for extended periods of time (like running to Argentina and back) that has detailed how they did it. I know there are some creative ways to get around a clogged DPF filter (like drilling holes in it for airflow).
If you're just doing Baja runs, you should be fine. Plenty of ULSD stations, and you should be OK running non-ULSD fuel for a couple tanks.