Rather than seaching on Realty Trac, your best bet may be to engage a realtor who can help you locate homes that ARE actively offered for sale, who can research information about the property, guide you through the buying process be this a regular, short sale or foreclosure.
If you are intent on buying a house at an auction at the county court house steps, then find the time to observe how it's done. If you haven't done this before, you may find yourself at a severe disadvantage, competing with seasoned investors/buyers.
If you can't go in person, then check out youtube and look for videos on county courthouse auction of real estate property to get an idea.
You can search all the homes currently on the market at the attached link.