In this paper, we explore how the application of multimedia design principles may inform the development of educational multi-user virtual environments (MUVEs). We look at design principles that have been shown to help learners manage cognitive load within multimedia environments and conduct a conjectural analysis of the extent to which such principles can help manage cognitive load in the highly immersive "beyond multimedia" environments that 3-D educational MUVEs represent. We frame our discussion as a design practice analysis of the River City MUVE, a science inquiry environment that has middle school students collaborating to develop and test hypotheses regarding illnesses sweeping a virtual town. We analyze the current River City interface design using a framework describing cognitive overload scenarios and associated approaches to manage cognitive load. We also discuss the potential difficulties that may be seen as multimedia principles are applied to 3-D MUVEs. Our discussion describes a blueprint for research implementations that we are undertaking to systematically investigate the effect of an educational MUVE interface design based on multimedia principles--implementations that we hope will provide an action framework for other MUVE researchers to use in their own studies.