Its easy (well easier) with motorcycles, as you can readily get fuel out of the tank, assuming you have some fire source. But for a car? Not sure.
Mind, for this specific case, you have to appreciate that these folks were rather far from the beaten path. They were certainly far away from the local ranger stations and what not. Ideally someone may have seen it and reported it, but I wouldn't necessarily guarantee it. They were in a pretty large valley where this happened.
And, as an anecdote, my friends and I were stuck near there for 3 days one year. But it was in the mud, in the nearby dry ("dry") lake, and we were near a road. Never in any danger. But it was a fun extraction.
Heck, forget the foreign country part. I'd be a lot more prepared for somewhere like Death Valley if I drove there from the East than if I flew there and rented a car.
Just what I would try, not really sure if you could get it hot enough. Maybe a lithium battery would add enough oomph?
I thought about using the upholstery or plastic panels from the dash etc. but that's probably all flame retardant on any modern car.