Search historical society archives and university collections for diaries of abolitionists and slave owners to see what they have to say. Slaves often told their own stories of escape after reaching freedom. Old maps will show you old highways and trails. Match these with modern roads, and then concentrate your research along the same paths that slaves might have used for escape. Finally, oral history can be most helpful.
People retain a great deal of history that never trickles down into the history books.
Go into your community and interview those who know anything about the local history of your area. If you don't have an historical society to help you locate people who have been in the area a long time, check with your local post office. The postman in a small communitiy often knows who the oldest living people are. Realtors can tell you the history of the oldest homes, and the names of the families who have lived there. It is vital that you let everyone know that you are doing UGRR research.