The land cost of the trips does not include domestic flights. You need a passport that is valid for more than two months after the end of the trip, and which contains more than two blank pages. Visa requirements and costs vary according to your nationality. Be sure you check this with your local agent or with the Chilean consulate near you. The visa should be obtained before your arrival to Chile.
Chile requires no vaccinations for entry from any country.
There is no malaria or yellow fever, the tap water in most cities is chlorinated and the general standard of hygiene is one of the highest in South America. The central Chile enjoys an idyllically Mediterranean climate, mild and temperate, the warmest months being November to February when temperatures reach 29 C which is always very comfortable due the lack of humidity.