The one thing I would have done differently is keep in touch with everyone. We drifted apart and did not keep in touch. Another thing I would have done differently is to ship my stuff in multiple smaller packages. As far as gaming, I do not think I would have changed anything.
Perhaps the one thing I regret is not trying to sell some of my adventures. I created a module, "The Key to Druid's Gate" in 1981. I ran it as a tournament dungeon at a local convention in Salt Lake City. We sold a few copies in the dealer's room.