Isalo National Park
The park is known for its wide variety of terrain, including sandstone formations, deep canyons, palm-lined oases, and grassland. The closest town is Ranohira, and the closest city is Toliara. A local guide is required for visitors entering the park, and guides and porters can be hired in Ranohira. Treks in the park can last from several hours to a week or longer.
Flora and fauna
Peter (+261 33 637 2392) was the best guide that we had in all the parks we visited in Madagascar. He was extremely knowledgeable, good at spotting animals (including small insects), and a fluent English speaker (I believe he also speaks German, and of course French).