When Iím up there I usually fish the west branch around Wilmington. Be sure to stop in at Fran Betterís place (Adirondack Sports Shop) in Wilmington and buy some of his original patterns (Ausable Wulff, Usual and Haystack). In addition to being a very innovative and famous fly tyer, he can give you directions on where to go and what to use.
This time of year hatches can be pretty slim with Tricos and Isonychia and blue wing olives being the main events. But a lot of the fishing is classic pocket water so high floating dries often do well like Wulffs and caddis patterns. Often the fish arenít too picky in the fast water sections. Stonefly and Isonychia nymphs are also a good bet. Isonychia patterns include classic stuff like Dun Variants, Mahogany Duns, and Iso comparaduns, leadwing coachman wets, and dark brown dubbed body nymphs (or stuff like Prince Nymphs and Zug Bugs come pretty close).
Thereís a 5 mile fishing C and R section along route 86 west of Wilmington that gets a lot of attention and is worth a shot, but the fishing below the CR section is often much better