From Ixtapa/Zihua airport, how would you get to Troncones without a car? Saw one trans company, but is @ $58US/person/one way. Any other suggestions? Thanks for any/all information.

I will let stewbear answer this !

It's an expensive proposition no matter how you go. Here is airport pricing.
http://www.zihuatanejo.net/airporttaxi.html This would run about $58 BUT up to 3 people not per person.

Now if your budget is tight a walk to the little café just outside the Zihua airport will save you some money. You should be able to negate with a local NON-Airport cab for around 300 to 350 pesos or at today's exchange rate about $25 US.
Airport cabs are fixed & no negotiation there.
Now if no luggage or just a carry-on you can bus it BUT from the airport that would require a bus Airport to El Centro, Then the La Union bus to The Troncones turn off & then a van into Troncones it's self.
Once there it is lovely & peaceful. One of our favorite day trips. For that the 2 bus trip from El Centro is a fun adventure.

Thanks, Stewbear. $58/one way/per trip (there's 2 of us) is not so bad when you look at the other rather inconvenient options. Looks like according to the accommodation we pick, we wouldn't need a car once we're there. Thanks, again.

Keep in mind that going back you should be able to get a cab for the 300 to 350 peso range.
Just curious where are you staying?