You can take Suburban Transit and NJ Transit from Somerset, NJ to New York City. There are tons of exciting things to do and places to see like the Empire State Building, the Met, the Statue of Liberty, Central Park, Time Square, Madison Ave, Broadway and much more. There is also some amazing food all throughout the city including in Chinatown, Little Italy, and Hell's Kitchen.
You can take Suburban Transit, Amtrak, and/or SEPTA down to Philadelphia. Philadelphia has a lot of activities to do and places to see like museums, the Franklin Institute (where we went on our first date), Old City, Betsy Ross's House, the Art Museum, the Please Touch Museum (for small children), and plenty more. There is also some amazing food in South Philly, Chinatown, and along Columbus Blvd.
Downtown Somerville is ~15 minutes from the venue and hosts an assortment of restaurants, bars, and ice cream, as well as historical locations and mural artwork.
Somerset, NJ has many historical sites to visit. Most, if not all, from the Revolutionary period. If you're a history buff, check it out!