Travelling in the State of Haidh

Beginning one's journey in the state of haidh

Q: I intend travelling from my home town to Johannesburg. I will stay for four days then leave for Pietermaritzburg where I will stay for 7 days then I will go to Durban for 6 days. I will leave my home town in the state of haidh. If I calculate my cycle, I should take a ghusal in Pietermaritzburg so I will read my Salaah in full. However once I leave for Durban, then will I read qasr or salaah in full as I don't think the distance from Pietermaritzburg to Durban is 77.7km. When I leave Durban I will go back to Pietermaritzburg and then to Johannesburg. Will I read qasr in Johannesburg? Please advise.