that certainly is the advantage when looking at doing routes that others have done before, just so you can get an idea of realistic travel times, surface variations, recommended tire widths, water availability and all that--- taking with a grain of salt whether the folks recommending it are super hardcore, very strong riders etc compared to what you know about yourself.
As. you have a fatbike, you probably know exactly how fatter tires very much suit some situations, and especially for an older guy like myself, I really value not getting the crap shaken outta me, so really like wider tires for the overall comfort thing, figuring if a lot is taken out of you if you really underbike it, it aint worth it--or conversely, worth it in the big picture for enjoyment of riding.
S.A- meaning South America? I've traveled in Latin America a fair amount (not SAmerica though) but can recommend trying to get as much info as possible with a route or area, especially if there isnt much bikepacking info, recent stuff, of a given area.