I traveled northern Sudan in December/January 2017 for two weeks with my 18 year-old niece. We used only public transport, except when visiting the archeological sights of Naqa and Mussawarrat. Going there you need a private vehicle, most likely a four-wheel drive which we shared with another traveler. We went as far north as Karima and stayed overnight in Khartoum, Shendi, at the Pyramids of Meroe and Karima. There are detailed blog entries on each of these places. To sum it up – one of my best trips ever.