Hi David,
I get my knowledge of Christianity from all sorts of sources, both Christian and otherwise, since I find it important to consider all points of view. You seem to be suggesting that I should restrict myself to the party line. I would say that means remaining blinkered.
I don't doubt that “the spiritual experience of Christ living in every believer is absolutely mainstream Christian teaching and doctrine”. But as I just asked, how many conventional (exoteric) Christians have actually found him?
Regarding what you say about Paul and Gnosticism, Much Gnosticism was also centred on Christ, so that does not disqualify him from being a Gnostic.
I obviously can't agree with your fear about Jung, although this is obviously the type of thing that Christians might think.
Visiting Jung's grave wouldn't be helpful. He was just a human being, albeit one of the greatest minds of recent centuries.