Lunch between West Chester and Hummelstown
Half way should put you right around Lancaster City if you take Rt. 30. There are lots of options there, with Rice and Noodles Vietnamese being most convenient. However, that probably won't be the fastest route, regardless of what Google Maps says, do to traffic patterns. The turnpike would be smarter, but that greatly limits your options to getting off at the 222 Lancaster exit, which is actually Denver, PA or waiting until you get off at the Lebanon exit - which is more like 2/3's of the way. And, IMO you'll get better food in Hummelstown/Hershey/Harrisburg then at either of those 2 stops.