I live in NJ, relatively close to sea level. I'm taking a trip to the Peruvian Andes and Brazil in a few months, and would like to adapt to the high (15,000 foot +) altitudes beforehand. There will be lots of intense hiking with loaded packs, and I don't want to have to stop frequently. I've researched hypoxic training, but most of the equipment is far too expensive. Any cost-effective suggestions?