Check with each county clerk for those records, or contact an information broker with database access to nationwide real property and mortgage records. If you feel the person may be deceased, an early check with the Social Security Administration master death index would save you many hours of research if your hunch is correct. Call them up. If they won't cooperate, there are services available to trace phone records from a given person which may lead you to the individual you seek. Try checking local registration records.
Women are usually more difficult to find than men since they change their names with marriage.
The County usually maintains marriage records. Only when you have exhausted all the public records in your search, is it time to turn to a professional.