Hopefully this will help: We went last November and loved it. We are a couple in our early 40's and have travelled a fair bit. Our itinerary was:
Day 1 day in Tana, booked small tour group for the following trip:
Day 2 Tana to Miandrivazo in van with group, stop for lunch in Antsirable (long day)
Day 3,4,5 Miandrivazo to Belo Tsiribhina along the Tsihiribihina river (lots of posts on this)
Day 6,7 4x4 drive to Tsingy (hot,bumpy and slow)
Day 7,8 little Tsingy and Grand Tsingy (lots of lemurs) then start the drive back.
Day 9 see Allee' des Baobobs, then continue to Morondava
Day 9,10 in Morondava
Day 11 fly back to Tana, start drive south to Antsirabe
Day 12 Antsirabe to Ambalavo (see Parc d'Anja, lots of ring tailed lemurs)
Day 13 Go to Parc National Andigintra, trek in the parc and stay overnight
Day 14 Trek out of parc, drive back to Ambalavo
Day 15,16 drive back to Tana
Usually to rent a car, you must have a driver as well. I can put you in touch with our driver who was excellent. To see what you want you really should fly, at least one way. The flight from Tana to Morondava is not that expensive and well worth it. Get your ticket in Madagascar, it is a bit cheaper than the website. The Malagasy are wonderful people, especially when you head out into the country away from the cities and towns. If you want more information feel free to message me. Apologies for the spellings, I don't have time to look them up again.