Been to many areas in Colombia, I believe Cocora Valley is the best place in the whole country of Colombia, despite the fact that coffee zone is becoming more and more touristy. Still you can easily spot the tranquillity there.
To go to the valley, the best base is the town of Salento. You’d better get up early, catch one of those early tuktuk at the central square, tuktuk can get quite full, sometimes you will have to stand at the back of the car, kinda fun though. Trail can be easily done in the morning.