We went with a driver and guide in Antsiranana from the port to Tsingy park to see the red geological formations .  The drive each way was a bone jarring 3 hours.  We did see the landscapes and villages and got a good feel of the area.  The guide did inform us of several facts along the way and was friendly.  At the park we had a 45 minute walk and got some water and fruit.  The price was comparable to a cruise ship excursion, so no deal, but we were not in a crowded bus and had our own guide.