I think I would like to DM once a week for my regular group and I would like to DM once a week for a school group of newer players with infinite time. I would also like to play one or two times per week in others games to avoid DM burnout. Each would be about 3-4 hours at a time. That is just playing, so I guess being the DM takes prep time with the two campaigns. This might add another 8 hours a week. Looking at this site and other D&D sites seems to already take up one hour a day as well. With infinite time, I guess I could also take up painting minis and designing more maps and terrain as well.