I strolled through this park on the way to and from the Cloisters, and it was a beautiful walk. You really feel removed from the city, and it isn't too crowded, being a bit off the beaten path. There are several pathways you can take to get to the same destination, so it's a place you could explore many times over.
The park overlooks the wide Hudson and the verdant ridge of the New Jersey riverbank on the other side. All along the highest paths through the park, you get excellent views from several different vantage points, often including the George Washington Bridge. At the park's summit is a grove of stately, old trees that makes for a perfect reading spot. There are winding pathways through densely-wooded areas, plenty of open spaces for picnicking and taking in some sun, and benches throughout. It's manicured, but not overly so - there's a nice mix of landscaped gardens and natural woods.
It's quite a ways from Manhattan's main tourist zones, but it's worth the train ride (take the A to 190th), especially considering the fact that you can visit the Cloisters on the same trip. For summer visitors, I would recommend planning a visit to the Cloisters until it closes at 5:15pm. The evening sun shining through the trees made the park even more beautiful on the walk back to the subway.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.