It depends what you are using it for, really. Since this is MSB, I will discuss MU/R20 interaction. It would be fairly simple to have r20 open alongside a MU client for most people. Even if the ONLY thing being utilized is the map/table aspect. There is no need to integrate character sheets unless you wish to use the native dice roller for r20.
If you wish to use it to support, say, a combat-heavy PRP, you could literally just have people sit in and look at the map, prompted through the game.