I've got a few hints. Have lots of coffee and pastries for your helpers before you start, and lots of food and beer for when it's over. That can make the difference between having fun when you move by bike and everyone feeling like it was a huge drag.
Have blankets out to cover your stuff before you tie it down. It's not really necessary, but sometimes it can hold a mediocre tie-down job together, plus you don't have to worry about stuff flying off the trailer when you're bombing down that hill. You can never have too many bungees. You can never have too many inner tubes to use as tie-downs. Those bungee cargo nets that they sell are really helpful. They come in 2 sizes: bicycle size and motorcycle size. The bike size is great for bike racks and the motorcycle size for trailers.
Some kind of radio or iPod set up that can be fastened onto one of the trailers for music makes it all go by quicker. Finally, if you're crossing any intersections where there's a traffic light or stop sign - you may want to seriously consider corking to keep the group from being split up. I don't want to "officially" encourage you to do something illegal, but I've seen situations where I felt it was far less safe to obey the law and be separated than to break the law and remain in a group. If that does happen, smiling, waving, and expressing your heartfelt gratitude to any inconvenienced motorists is strongly encouraged.
Here's a photo set of a bike move to give you some visuals. Have fun.