As a Peekskill resident, Blue Mountain Reservation is a fun escape from the noises of the city and pace of modern life. I've hiked many of the trails and they can be a bit rocky. There are Mt Bikers, runners, and sometimes horses too. There is Verizon LTE for just about all of the park and Google Maps can guide you with a trail map otherwise the trail junction numbers are nonexistent. Blue Mountain has a nice view from the top and is an easy hike following the blue trail from the back parking lot.
print your trail map before you get there. also, you can park on the back side where Old Montrose Station Rd dead ends at the park and enter for free. This is where the locals go.
mt. spitz gives you a super view of the Hudson and is a 30 min walk up from this back entrance. There's an old stone bldg at the top. no idea what it once was.
Shawn A. on Blue Mountain Twin Summits Trail
Yes, everyone loves these trails for mountain biking, but they are great for trail running as well! Some of the best in the area. Only downside is they do get very muddy if there has been a lot of rain.
Clearly stay away from the shooting range, but otherwise there are plenty of trails to run on that offer a decent variety of terrain.
If you are new to trail running, try running Montrose Station Road. This is mostly gravel and can be picked up at the intersection off of Washington Street. The initial ascent up Montrose Station Road is steep, but it levels out about 0.5 miles in.
Just keep an eye out for mountain bikers!