Angola

Hi, I’m heading to Angola for two weeks starting mid-April and I’d like to rent a car to explore the country, but not a 4x4 to keep my budget in check. I plan to mostly stay in the western part and go as far as the Namibian border. Is it possible to drive in Iona Park without a 4x4, or to get to Kalendula or Piedra Negras? Also, is the Lubango–Huambo–Kuito–Malanje route doable in a city car? Lastly, do gas stations accept Visa? Thanks for your feedback and tips!