San Vicente del Caguán is in Caquetá. The former FARC capital of El Caguán DMZ, it isn't a tourist attraction, but does make for a convenient stop over when en route to or from La Macarena.
The only straightforward way in is by land. Possible my water also, but this is much more complicated.
The nicest hotel in town seems to be Hotel Amazonia Real. It also seems to be the most expensive, at approx 65,000 Pesos per night.