The role of neither the vocations director nor a spiritual director is to tell you what to do with your life. Their job also isn't to tell you what God wants to do with your life. Only you and God know what God is saying to you in the silence of your heart. Their job is to help you in the process of understanding God's will and to give you the tools to act.

The vocations director helps with matters in the external forum (i.e., information regarding the applicant and the process of formation that may be discussed with the bishop) as a mediator between you and the Church. He connects you with the bishop. He helps facilitate retreats, pilgrimages, vocations events, etc. He also assists you with your educational process and pastoral assignments. These are all external realities that applicants to the priesthood experience. These realities are necessary, but they shouldn't be unnecessarily burdensome or complicated. Bureaucracy shouldn't get in the way of an applicant's formation, so the vocations director intercedes on behalf of the applicant to the Church. He also intercedes on behalf of the Church to the applicant. Depending on the size of the diocese, it can be difficult for a bishop to be well acquainted with all of his seminarians. Therefore, the vocations director is delegated to give the bishop an accurate report on your formation, so that, if the day comes for your ordination or consecration, the bishop is confident that you have been well formed.

A spiritual director, on the other hand, assists you in the internal forum (i.e., those things that, if you choose, are known only to you, him, and God). Ideally your spiritual director is also your confessor. This helps with transparency and gives him a window into your struggles so that he can effectively help you accept God's call, whatever that may be. The spiritual director does not speak to the bishop about your formation; he does not have a "vote" on whether or not you should be ordained or consecrated.

That's a simple overview of two important figures in the process of formation to the priesthood.