I am planning to visiting several ancestral small towns including: Hambach, Diedesfeld, Stockach. I would appreciate finding out how to prepare for the visit.
I would take a look at this link. It is a great place to learn about this country it describes what kind of records are available, it's background, enjoy it:
There are several Hambach's in Germany. Which state is your Hambach in?
If you want addresses to visit, try civil registration (addresses were not always recorded) and directories. Contacting a local genealogical or historical society is a good idea. Note that Europeans tend to clear graves after a period of time (due to a lack of space in densely populated areas), therefore the chance of seeing gravestones of relatives from more than 100-150 years ago is slim.
Thank You for your question, there is a lot of Information on Wiki, go to Europe find Germany, and put your question into the search bar. There are many groups that you can join to find the correct information that you are looking for.
I hope this will help you before your visit to Germany