Hare Krsna Dear Gurudev,
    Please accept my humble obeisances at your lotus feet.

HpS - ASA -- Apple flower feet, maybe.  We still eat improperly, but progressing.

    All glories to Srila Prabhupada.
    All glories to Guru parampara.

    Gurudev, We hope you are good in health and doing well.

    I am thinking to do PhD (through correspondence). what you would advise?
    
your fallen servant,
Girivaradhari-Gopal Das

HpS - Hmmm!   It is a big question.  It is like I am thinking of buying some land.   What is your personal motivation for doing it?    Who inspires you to do it?    Who would be your associates if you did it?   Who would benefit if you did it???