  We introduce two new methods that are designed to improve the realism and
utility of large, active region-scale 3D MHD models of the solar atmosphere. We
apply these methods to RADMHD, a code capable of modeling the Sun's upper
convection zone, photosphere, chromosphere, transition region, and corona
within a single computational volume. We first present a way to approximate the
physics of optically-thick radiative transfer without having to take the
computationally expensive step of solving the radiative transfer equation in
detail. We then briefly describe a rudimentary assimilative technique that
allows a time series of vector magnetograms to be directly incorporated into
the MHD system.
