Perhaps you don’t know this, but Philadephia has a very large collection of Darwin literature — it only makes sense, since in the early years of our country that city was the center of science and philosophy in the US. The American Philosophical Society Museum is having a major exhibit of those artifacts, so you should get down to Fifth Street and amble through. If you can’t make it (regretfully, I’m stuck in Morris for a while), they have an online tour.