The first week in June would be best.
Neversink Caddis- Yellow. #16
PA- Olive and Grey #14-18
Stimulators- orange-yellow #16
BWO- #18 If in April
Yellow stoneflies- #16-18
Possible Green drakes in May...10-12
Nymphs- Only if nobody is watching.....
Green and tan caddis puppa
Dont forget some SJ worms...greenie weenie(pink-green)
That should cover you.
If the flow is up or blown out....dont forget some streamers.
My boxes are 800 miles away....
. It wouldnt hurt to have some March Browns...Quills...light Cahills. Springtime in the Smokies-- I might carry 30 or so patterns.