Genesee River (Charlotte Area) is a 3.8 mile trail located near Rochester, NY and is good for all skill levels. The trail is primarily used for walking and canoeing and is accessible from June until November.
There is a nice path that starts about where the current Charlotte bridge is and runs toward the city along the river. A little stretch (maybe 1/4 of a mile) of the trail goes out onto a wooden path that runs through the water. There are some nesting swans down there, other birds and the occasional snapping turtle.
The Charlotte park and pier out to the lighthouse is a nice walk too, but the points between these two trails isn't too pleasant because your walking through traffic and parking lots and if you don't know the river path is there, your going to miss it. On the plus side, there are plenty of restaurants and burger joints around to get something to eat. The park also has a vintage (1915?) carousel that operates during the summer.