Day 0 - Arrival
Day 1 - Arusha
Day 2 - Lake Manyara
Day 3 - Ngorongoro Crtr
Day 4 - Tarangire NP
Day 5 - Arusha
Day 6 - Kilimanjaro, d1
Day 7 - Kilimanjaro, d2
Day 8 - Kilimanjaro, d3
Day 9 - Kilimanjaro, d4
Day 10 - Kilimanjaro, d5
Day 11 - Kilimanjaro, d6
Day 12 - Arusha
Day 13 - Departure
Tanzania
Day 4 on the Machame route is from Barranco Camp (12,956 feet) to Barafu Camp (14,924 feet) via Barranco Wall.
More snow and more high altitude, and some actual interesting scrambling up Barranco Wall. Rock climbers like us got to feel right at home-- even if it was quite a bit short of anything resembling actual climbing, it was still a refreshing break from just walking!
Add in a second half where the terrain bore a vague resemblance to the surface of Mars or some other area where NASA might have previously tested interplanetary rovers, and aside from the high altitude, it wasn't a bad day at all.