Three days: visiting Tarangire NP, Lake Manyara NP and Ngorogoro Crater.
Four days: 3 days stunning Serengeti NP, 1 day Ngorogoro Crater.
Five days: 1 day Tarangire NP or Lake Manyara NP, 3 days Serengeti, 1 day Ngorogoro Crater
Six days: 1 day Tarangire NP, 1 day Lake Manyara NP, 3 days Serengeti, 1 day Ngorogoro Crater
Seven days: 1 day Tarangire NP, 1 day Lake Manyara NP, 4 days Serengeti, 1 day Ngorogoro Crater
Eight days: 1 day Arusha NP, Tarangire NP, 1 day Lake Manyara NP, 4 days Serengeti, 1 day Ngorogoro Crater