Drive out through the northern parks, then skip the long return road trip entirely with a scenic light-aircraft flight back from the Serengeti to Arusha.
Arusha to Tarangire National Park — afternoon game drive.
Tarangire to Lake Manyara National Park — afternoon game drive.
Full-day Ngorongoro Crater tour, overnight on the rim.
Drive to the Serengeti, afternoon game drive.
Full day Serengeti game drive across the central and northern plains.
Final morning game drive, then a scenic light-aircraft flight back to Arusha.