Fall River is the one place that is in the very best shape of the all the rivers and streams in our region. No outside influences and spring fed makes it stable as stable gets. 
Like the Met, PMD hatches are springing to life here too. BWO’s, Midges (Black #22-24), March Browns, Ants, Beetles, Hippie Stompers and a fair number of Caddis are all good. 
Euro Streamers and Euro nymphs are the hot stuff. Eggs and Mops are great too. 
Spread out, Fall River is not just the hatchery. Go explore and hunt fish in different areas. They may not be stacked up like at the hatchery, but lot’s of places hold a fish a 2 and that is more realistic of what Spring Creek Angling ought to be. Think of yourself as a NZ guide, sneaking up on water than has one or 2 fish and you gotta get it right with a good fly choice and a great cast.