Hi! I wrote the post. Good answers below. Decent generic mountain bikes with disc brakes are found all over South America, being pedaled by casual riders and kids in the town squares. Starting a tour with that equipment and adding racks and such would be affordable, and parts will be replaceable. Surly/Soma/Kona/Salsa/Fuji/Etc. touring bikes come with the main advantage of mounting points. But more DIY riders are rigging things up with hose clamps.