By River to the Amazon
There's plenty of opportunity for great adventure in Colombia, be it mountain climbing, extreme sports or diving in the Caribbean, but if you're looking for the ultimate adventure then it's hard to imagine anything more challenging and exciting than the epic river journey from Los Llanos to the Amazon. This is a trip through almost total wilderness, where the largest settlements are remote indigenous villages set among hundreds of thousands of square kilometers of dense jungle, fast-flowing brown rivers and thick humidity. It's only become possible in recent years as guerrilla and paramilitary camps were gradually abandoned as part of the peace process.
While the journey is now possible, it's still a long way from easy or particularly comfortable, and you'll need at least two weeks to complete the trip from San José del Guaviare to Leticia, not to mention plenty of run-up time to arrange transportation through a travel agency. Attempting this without logistical support from an experienced operator would be extremely dangerous.
Contact travel agencies in Leticia to inquire about making the trip. Alternatively speak to staff at hotels in San José del Guaviare and ask if they know reliable guides. Either way ensure you begin the process several months before you want to undertake the journey and follow the travel agencies' advice regarding any changes in regional safety.
Los Llanos is way behind the rest of Colombia in terms of tourist infrastructure; for now, hotels in the region are, in general, fairly simple and unmemorable. A local hostel scene has also not developed, though it will likely arrive very soon as traveler numbers to the region continue to increase.
Carnivores will be in heaven in Los Llanos, though vegetarians markedly less so: as the center of Colombia's beef-rearing industry, it's all about carne llanera on the dinner table. Many vegetables used elsewhere in Colombia don't grow in the region due to the harsh weather conditions, and so expect to see a lot of avocado, plantain and yucca accompanying your meals.
Drinking & Nightlife
Llaneros love a drink and a dance, and so even in small towns in the region you'll often find raucous cowboy bars and dance halls packed with locals. Villavicencio and San José del Guaviare are both large urban centers where cowboys come to spend their weekends off, and so you'll have plenty of opportunity to join the party if you want to.