At the Letort expect to fish subsurface and anything you find rising on top is a bonus. You can prospect with dries and you may actually bring something to the top now and then but if you want the best chance to catch fish go subsurface and bring scuds – lots of scuds – in various shades of olive, gray, amber, orange and pink in sizes 10 – 19 (yes there are size 10 scuds and the trout know it). And also bring thinly dressed sulfur nymphs in various shades of amber/tan/olive in sizes 12 – 16. And as others have said, bring lots and lots of patience, especially at this time of the year. As the weather warms the stream’s channel narrows due to weed growth and the grass and other assorted vegetation on the bank grows high and can be quite bothersome. In fact, in certain sections (especially in the Bonney Brook area) your biggest challenge will simply be getting close enough to the stream’s edge to be able to get your fly in the water without first spooking everything. Sulfurs and assorted midges of frighteningly miniscule proportions may be hatching in certain sections but don’t expect intense blizzard like hatches like you would at a freestone. Your best success for finding anything on top will be to pick a section of water where you can watch – don’t fish just watch – and if you see something rise, figure out the best way to position yourself in casting position and make the first cast count.
More than anything the Letort will test your trout stalking skills because you have to get relatively close to the trout to be successful. You can’t aimlessly fish the water or you will spook everything within 100 yards of you so you have to stalk the trout. At the Letort you spook one fish and that fish takes off and spooks another, which spooks another and first thing you know your one misstep has spooked 100 yards of stream. And because of the channels and the tricky currents forget the long distance casting and concentrate on working sections of stream in small increments. If you attempt to drift a scud much more than 5 feet at a time more than likely you will be spending the majority of your time pulling your fly from the weeds.
If you fish streamers (another good choice), fish them slowly and methodically. The fish in the Letort are not going to chase a streamer ripped down, across and up. With streamers you are targeting specific areas where the trout may be holding and presenting it in such a manner that it can easily be intercepted. Suggested patterns are always a Shenk’s White Minnor and then thinly dressed ones like a black nose dace, mickey finn, black or gray ghost, etc., and then some bulkier ones like a muddler, woolly bugger, etc.