How do I proceed with my search?

Am trying to find the father of my 4 great grandfather. It is a very common name (John Brown) and there were literally dozens of them in the early 1800's. How do I identify this person or track this person down without a wife's name, no birthdates and only a general location (Highland County, Ohio). Have hit a brick wall and would like advice on what else I can do (other than going to that location and looking through journals/records at some court house or library - which is in my future plans) that might enable me to track this person down? I have tracked every John Brown that was born from 1770-1815 which would be the age bracket to have a child in 1831. Where do I go from here? Have tried wills/land purchases/census reports (those are no help when you don't have any knowledge about how many kids they had and can't match a 5-10 year old male in the household in the 1840 census reports. Ideas????