The only way to find the "old stuff" is to get out there and find the old sites. Where did people gather 50 years ago, 100 years ago, 200 years ago??? Old parks....school yards, fairgrounds...you get the idea. Old aerial photographs can offer some great clues. One of my favorite web-sites is:
www.historicaerials.com. Its like having your own personal time machine! Good luck and HH