What are my rights as the heir to my grandfather's estate?

Unless your grandfather had a will which had specific gifts to you, you are not entitled to anything of your grandfather's in your own right as he predeceased your father. However, you do have a right to probate your father's estate and possibly make a claim on your grandfather's estate in the administration of your father's estate. The real problem is the time that has elapsed. Applications for traditional probate must be made within 4 years of the death of the decedent - your choices in how to act on your father's estate are now limited.

First, I would make certain that a will has not been probated or that an estate has not been opened. Generally, the county clerk can tell you if a will has been probated. After the county clerk confirms nothing has been done to settle either of the estates, I suggest you contact an attorney. You will basically need the help of an attorney to open back-to-back estate administrations for your father and grandfather. Note that this could be fairly expensive to do. Although the estate generally pays for the cost of administration (court costs, attorney fees, etc.), this could be a challenge if you don't have possession of any of the estate property.