There is a boat launch at the
Ulster County Fairgrounds (former "County Home" shown on the topo) on Libertyville Road. The fairgrounds are just south of the town swimming pool. Use gate C (next to fair office, a white house) shown on this
map. A paved fairground road, not shown on the map, heads straight to "29" where a gravel road winds down the hill to the Wallkill. In order to drive to the launch you would need to avoid the dates when the fairgrounds are in use:
Saturday, June 30, 2007 (July 4 celebration and fireworks)
Tuesday-Sunday, July 31 - August 5, 2007 (the county fair) and several days of set up before and after
Friday-Sunday, August 17-19, 2007 (Hudson Valley Ribfest, food festival)
Memorial Day and Labor Day weekends (craft fairs)
Sunday September 16, 2007 (Taste of the New Paltz, food festival)
A short distance further south, the Wallkill is adjacent to Libertyville Road - which might provide some access. At that point the water is fairly shallow with some boulders in the river.
There is a
campground on the west side of the Wallkill in Gardiner, on Bevier Rd, via CR 9, just south of Route 44/55. It has a river access site within the campground. I don't know of any formal public access near Gardiner.