The most happening spot in town (and the only place you'll encounter other gringos) is this hostel with colorful wall murals, fast wi-fi, a small pool, an outdoor gym, a shared kitchen, pool and ping-pong tables, inviting hammocks and, most importantly, sweeping river views. Dorms are a better deal than the rooms, some of which have zero furniture beyond the bed.
Hostal Mirador
Top choice in Amazon Basin