John S -
Maxwell worked on several Philly area golf courses. At Pine Valley he did some work on the right side of the 5th green, the small green on 8 and the left green on 9. He also did several greens at Philly CC. Only a few of those probably are in tact as Flynn came back in behind him and redid some of those. Also, there is Melrose, which was an original design with some input by Mackenzie. Some of the routing is in tact, but I'm not sure how much of his original greens remain. I would think the 17th green would be original, but beyond that I would be a little suspect. He did some other work on a couple of courses that NLE as well in the area. Maxwell actually maintained an office in Elkins Park.
Also, he redid a couple of holes at Saucon Valley on the Old Course (11 and 12 I believe but the course may have changed the order of the holes since I last looked).