we do a lot of Plant-to-Plant Transfers - using Inventory Transfer (moving from warehouse to production plant) is there a saved search I can whip up to see how much inventory we are moving?

Yes there is, going over some of the basics of Saved Searches will help you understand your system better as well as solve for this need. A good start would be to make a Transaction Saved Search, and set a "Type" criteria to the types of transactions you are looking for (Inventory Transfer) then refine your details from there.