First thing, go by Fran Betters Shop, Adirondak Sportsman - the guy is an icon of sorts who invested the Haystack (which became the Comparadun), the Usual (which is great anyway, but started the shoeshoe rabbit thing) and a host of other flies. The shop is definitely out of the 50's - cluttered, and his flies are not pretty - they just catch fish. You can get info on the river, etc. He has a website - search for Ausable to find it.
Generaly Ausable is pocket water, with some pools in between. Expect shorter, more accurate casts in most places. Tons of stoneflies in the water, a good caddis river, and probably the best Isonychia river I know.
Lets assume worst case - mountain thundrstorm blows out the river. Lots of ponds loaded with trout if you don't mind a little hike - esp. if you have access to canoe or float tube. Good luck and have fun.
Oh, by the way - if you are up there in late Spring, some great mayfly hathces, esp. Green Drakes and even Hex on the ponds and lakes. ALSO, HOWEVER THE HOME OF THE BLACKFLY _ SO BRING DEET!
