Both of these are good access points with ample parking and clear trails up and down the river. Remember to explore a little so you can escape the crowds. The whole river contains fish and the further away from the popular spots you go, the more likely you are to find eager trout. If you don't have your own transportation, you can take the train to Brewster Station and then walk about a third of a mile down to the Borden Bridge access point. My friend makes this trip frequently and finds it quite convenient.
Trains return to the city about every hour and the ride takes a little more than an hour.
The trout in the Croton enjoy eating all the usual eastern insect imitations. Later in the summer be sure to bring some crickets and grasshoppers. There are a few motels in Brewster and ample places to get a decent meal. Call the Brewster Chamber of Commerce for more information. I haven't been able to find any sport shops in the Brewster area.