Although most people will start their gap year in South America by plane, there are other options for reaching the continent, giving you full control over your itinerary.
The best way to travel to South America from overseas is to fly. The amount of international flights into the continent has greatly increased in recent years, and most backpackers arrive in Rio de Janeiro or Buenos Aires and go from there.
Some countries in South America like Paraguay and Suriname can still be difficult to reach, often requiring you to fly somewhere close by and travel overland.
It's surprisingly difficult to get into South America overland, as the only way to do so is from Central America. There are no roads or railways that connect Panama to Colombia, though it is possible to ship your car over by ferry if you're feeling particularly determined.
It's possible to take a ferry or cruise liner from the lower Caribbean into South America, although this is rarely a cheap option. The same can be said for coming down from North or Central America - these trips are usually pleasure cruises rather than pure transport.