I just posted the answer of Colin B. Donovan, STL from EWTN several posts ago:
What the Church permits. As the already cited statements note, Catholics may go to Medjugorje. Such pilgrimages may even include priests acting as chaplains, as opposed to officially sponsoring them. Also, the Church has not suppressed discussion of Medjugorje, therefore, it is allowed. Common sense, however, says that Catholics on both sides of the Medjugorje issue should exercise prudence and charity in speaking of others who believe differently. Medjugorje is not a litmus test of orthodoxy, though every Catholic will have a moral obligation to accept the judgement of Rome, in the manner Pope Benedict explained, should it ever be rendered.
St. Augustine probably gave the simpliest and most helpful rule for all matters of the Church’s life when he said (in my paraphrase):
In necessary things unity,
in undecided things freedom,
and in all things charity.