Question
When I test the zones individually, all sprinklers are functional and there is no pipe shaking. When I let the system go through the full scheduled sequence from zone 1 to zone 6, pipes near the main outdoor valves shake only when the system transitions from zone 5 to zone 6, severe enough for me to have to turn it off immediately. The entire system worked fine last fall. Any thoughts on how best to troubleshoot?

Additionally, the pipe shaking has caused about 1-2 ozs. of water to leak out of an overhead powder room fan that is about 10 feet away from the main outdoor sprinkler valve but also about 10 feet higher than the sprinkler valves. Do you think it is safe to assume that the water leakage from the overhead fan is not from sprinkler pipes but possibly from the pipe vibrations causing another problem?

Answer
The pipe shaking is probably a pressure differential situation that should be resolved if you adjust the flow on the irrigation valves.  Do this by opening the flow control all the way, then close it all the way, counting the turns.  Then open it back up halfway.  The leak is another matter.  I dont see how the house plumbing would be so strongly affected by the shaking, but stranger things have happened.  Either check it out yourself, or get someone to do so very soon.