i have a question about how much time someone would get if they were indicted from a grand jury for illegal conveyance of prohibited items onto ground

The penalty depends upon what is alleged to have been brought into the facility.  If they are alleging drugs or weapons, it is a Felony 3 and there is the possibility of 1 to 5 years in prison.  If it is a cell phone or a two-way radio, it is a Felony 5 and you could get 6 to 12 months.  Cash and liquor are misdemeanors with significantly less time.   The information provided in this answer is provided for general information only; the information provided should not be construed to be formal legal advice nor the formation of a lawyer/client relationship. It is strongly advised you contact a lawyer in your geographic area to more fully discuss the issues raised in your question.