I'll be developing a documentary photo and video project on farming communities which live +3000 meters above sea level, based mostly on portraits and images of everyday life. At that elevation, the sun is really strong, producing sharp shadows and high constrast most of the day.
I'll be working alone, and my lighting equipment is: one Yongnuo YN-568EX II flash, a small 5-in-1 reflector/diffuser, and a thermal blanket (yes, I said a thermal blanket, it's a thin plastic [mylar] blanket covered with reflective material, designed for body heat keeping but perfectly useful for light bouncing).
I'll be mostly working on open locations, having no near buildings to act as reflective surfaces.
I won't be able to suit all of my work at dawn and dusk golden hours, as I depend on the times of farmers' activities.
Which is the best way to ensure having well-lit subjects, avoiding hard shades from wiping out their expressions, or hats shading completely their faces, whithout getting too artificial-looking images?
In case this can't be achieved, are there ways of creatively using those shadows? I'd be glad to know examples.