Even if you're working the 9 to 5 grind in NYC, you can still escape the city for 48 hours most weeks. And if you're a true outdoor enthusiast, you might be best served to head an hour or so outside of the city for awesome activities and a one-night camping trip to keep you away from the craziness of Manhattan for just a little longer.
If you want to go hard
Serious hikers should consider heading north to the Appalachian Trail for a two or three day hiking stint. You can take a train from Grand Central with your gear and do a long out-and-back hike, but remember to pack enough provisions, since it's seriously rustic territory. You'll likely end up feeling like you want to start from the beginning and hike the entire thing by the end of a couple days, but even just a weekend outing is worth it for the adventure, and for the people you'll meet and stories you'll hear!
To combine the Trail with a slightly-less-rustic camping setup, consider the Delaware Water Gap or Harriman State Park: you can do part of the Trail from both parks (more on that in a minute) with actual bathrooms and easy access to food and water.
If you want a relaxed weekend outside
Feeling beach-y, with a hint of mountain or road biking? Try Sandy Hook . You can take a ferry over from the city or make the drive, then set up a tent and enjoy the scenery (just watch out for the clothing-optional beach!). The beach is fantastic, and the Hook is long and flat, perfect for looping a few times on a road bike if you want to go easy, or road running. Just outside Sandy Hook is Hartshorne Park , which has some of the best mountain biking in New Jersey, and is perfect for hiking or trail running. The roads in the area are fairly cyclist-friendly as well, if you want to put together a road ride. The beach is perfect for a finishing run before collapsing on a towel and soaking up the sun, and there are some great seafood places (and hot dogs right by the beach) so food isn't an issue!
For a family-friendly good time
If you're hoping to get the kids and your significant other into outdoor adventuring, the Delaware Water Gap is a fantastic choice, since it caters to nearly every activity you could possibly want to do, and offers some campsites with great amenities. There are easy—and challenging—bike loops, both for road and mountain, as well as hiking trails in all shapes and sizes, with serious climbs or wide paths, depending on how intense you want to get. There's rock climbing as well, and plenty of water sports if you want to rent a canoe or kayak . It's an easy trip, and no one will get bored, guaranteed. Plus, the park is so enormous that you could go weekly all summer and still find new stuff by the end!
Closer to the city, consider camping in Harriman State Park: plenty to do, from canoeing to hiking to beautiful road riding, and it's only an hour outside city limits!
If you can't take the time
Just head to Brooklyn and camp at Jamaica Bay . You'll be just a stone's throw from the city in case of a work emergency, but the campsite is still rustic enough to feel like an adventure. You'll have to work to remind yourself that you're on a camping trip, since it's still a pretty urban area, but there are plenty of fun opportunities in the area: The Rockaway Gateway Greenway runs near the park, and the multi-use trail is a great road ride or run spot. For hiking, don’t miss the Dead Horse Bay or North Forty Nature trails. Swimming is available (and excellent!) over in Jacob Riis Park during the summer, so bring bathing suits—and also during summer weekends, there are free kayaking programs at the campground, so make sure you take advantage of that! If you get rained out while camping, the Aviatior Sports Center nearby has indoor climbing and basketball courts.