this seems like a relatively straight forward project. yes it will be invasive to the landscape and the system, but something that can be worked out pretty easily. make sure you size the new main large enough to allow multiple zones running at once. markout all the mains and VB's and make some copies. then start drawing the new main and note all of the road blocks. it may take a few sketches to come up with a workable pipeline path. i wouldnt worry too much about hitting pipes and wire. try to minimize the damage, and make sure you either pad enough in the estimate to cover repairs or write in that repairs will be handled on a TM basis.