Road trip - advice/suggestions (Bogotá)

So, a couple of friends and I are planning a short road trip through parts of the country in April and it would be great to getting some advice/suggestions based on past experiences - sort of like the do’s and don’ts. Also, if you know of any places on the way that are definitely worth stopping for.

The journey is straightforward – start from Bogota through to Bucaramanga (1 night), to Tayrona National Park (2 nights), to Cartagena (2 nights), to Medellin (3 nights), to the coffee region (3 nights) and back to Bogota.

The stretch from Cartagena to Medellin is a fairly long one, while we don’t want to stop for a night on the way down, any suggestions on places that are worthwhile stopping for a break?

Also, in the coffee region – any recommendations on places to go? We will have a car, so will be fairly mobile to hop around.

Thanks!
Adnan.