Even though there is a lot of great insights and advice in the books of Rav Nahman, still there area few areas where there is a problem. The idea of "graves of the righteous" seems to be problematic. See the Nefesh Hachaim of Rav Chaim of Voloshin [a major disciple of the Gra] that one that intends to tie his soul with even the greatest of saints is doing idolatry.
There is some aspect of "being connected with the soul of a tzadik" that is a problem. And even more so the soul of a saint who has died.
The reason is there is a sort of "kelipa" [force of uncleanliness] that is attached to people that have died. {Normally this is called the "angel of death".} So we hope the souls of our loved ones who have passed on have found a better world to exist in. But in this world, there is a sort of uncleanliness that is attached to the dead. You might take a look at the Book of Numbers to see this and also in the Mishna Seder Taharot, tractates Kelim and Tents.
On the other hand there is plenty of advice in the books of Rav Nahman that I find to be indispensable. sine qua non. [Private talking with God, method of learning, etc.]
