Improved accessibility to the microkelvin temperature regime is important for future research in quantum materials, for quantum information science, and for applications of quantum sensors. Here, we report the design and performance of a microkelvin platform based on a nuclear-demagnetization stage, engineered and well optimized for operation on a standard cryogen-free dilution refrigerator. $\mathrm{Pr}\mathrm{Ni}$${}_5$ is used as the dominant refrigerant. The platform provides a large area for mounting experiments in an ultralow-temperature low-electromagnetic-noise environment. The performance is characterized using current-sensing noise thermometry. Temperatures as low as $395\mu K$ are reached and a protocol is established in which it is possible to operate experiments below 1 mK for $95\%$ of the time, providing an efficient cryogen-free microkelvin environment for a wide range of science applications.