Just the other day I was reading something that may be useful to you.
QUOTE
Finally, if a spiritual guide cannot be had or if spiritual advice can be had but at rare intervals, a treatise on the spiritual life will, in a way, take the place of spiritual direction. There is no doubt, as we shall repeat later on, that spiritual direction constitutes the normal means in the training of perfection. But if for some reason or other one is unable to find a good adviser, God provides for the lack; and one of the means He uses is precisely some such book as points out in a definite and systematic manner the way to perfection. - The Very Reverend Adolphe Tanquerey, The Spiritual Life: A Treatise on Ascetical and Mystical Theology
A good spiritual advisor recommended to me
The Spiritual Life: A Treatise on Ascetical and Mystical Theology. It covers, I believe, everything. I have had it for a while and found it so helpful. It has about 760 or so pages. Very, very good. It was actually written for priests and seminarians to teach them about the spiritual life and how to guide and lead souls. You may find it good also because you hope to become a priest and you very well could be a spiritual director in the future.
There is another book like it called
Mystical Evolution. It comes in two volumes. I have only been able to flip through it. It is a classic when it comes to the spiritual life though. When flipping through it I found that it answers so many different questions I have been having. You will probably find it helpful. It is a lot like the previous book mentioned.
Then there is another classic on the spiritual life called
The Three Ages of the Interior Life by Reginald Garrigou-Lagrange, O.P. Pope John Paul II actually studied under him. Very wise and holy man. The book is pretty similar to the previous two mentioned. It is two volumes as well. It is a "synthesis of Christian Perfection and Contemplation and Love of God and the Cross of Jesus."
The three men who wrote those books above were holy men. All are very, very indepth looks at the Spiritual Life. They are pretty thick, and I don't know if you could encounter something that those books could not help you with. If you do though, I am sure our Lord will take good care of you and lead you to the books or persons that will help you. If your looking for, as Tanquerey suggested for those without an sd, a spiritual treatise that will or could replace a spiritual director - those are the books to go for. Also, I wanted to post something too I found in the introduction of
The Spiritual Life, a couple paragraphs above the quote at the beginning of the post:
QUOTE
...Nevertheless the study of Ascetical Theology will be most useful to them [the laity] for three good reasons: - a) In order to stimulate and sustain the desire of perfection as well as to give a definitive knowledge of the Christian life and of the means which enable us to perfect it. No one desires what one does not know, ignoti nulla cupido, whereas reading spiritual books creates or increases the sincere desire to put into practice what has been read. Many souls, as it is well known, are ardently carried on to perfection by reading The Following of Christ, the Spiritual Combat, The Introduction to a Devout Life or the Treatise on the Love of God.
Maybe those last books mentioned will be of some use to you as well.