Pack Monadnock in Miller State Park in Greenfield NH is pretty awesome. Its 1 1/2 hrs from Arlington, so its probably closer for you. Pretty good hike, not too tough, but awesome views!
Mount Monadnock is in that area too, but its a little further, and a little tougher, but definitely a really good hike. It gets kinda steep at the top, but when we went, there were all types of people hiking there, young, old and anywhere in between. You'd probably be fine if your in decent shape.