I have worked in the field both in the US and in Central and South America. Of all the vehicles I have used, the Toyota Tacoma would be the best option. Small truck, reliable the engine is not that big so mileage is not that bad and excellent in the mud> I have made the diesels go trough stuff that I was 100% percent sure I would have to winch myself out of. The Subarus are ok but if you want cargo capacity you should consider the Tacoma. The 4WD double cab, diesel would be my choice. This is work horse.
Cheers, Naikoa