Separators and mixers for delivering controlled-quality solar-generated steam over long distances for enhanced oil recovery, and associated systems and methods. A representative method includes heating water to steam at a solar field, separating a liquid fraction from the steam, directing the steam toward a target steam user via a first, steam conduit, and directing the liquid fraction toward the target steam user in parallel with the steam via second, liquid fraction conduit. The method can further include mixing the liquid fraction and the steam before delivering the combined liquid fraction and steam to the target user.