Salaam brother, It is better that your wife is honest with her parents and that she explains to them about her marriage and her conversion. Seperation is uncalled for and she can try and achieve that what she intends to achieve by introducing you to her parents and then giving them time to take in this news. As a parent, it would be quite overwhelming to hear that your child has married without your involvement. This is not easy to deal with for any parent. So time should be given for the parents to 'digest' this news before making efforts to introduce them to Islam. Your wife can demonstrate what Islamic life is all about as she interacts with you, prays, follows the prescribed ways. By observing her peaceful and orderly life with you they will become more acquainted with Islam. Your wife can then take her time to further answer their questions and with your help, invite them to Islam.
Approaching this whole matter in the way that your wife has mapped out in her mind may cause a long term of seperation between the two of you and it is not recommended to be seperated for long periods. In addition, although your wife has not yet informed the parents regarding her conversion, she still needs to observe her Islamic way of life during her intended stay with her parents, and this will become difficult for her as they are living by a different set of rules which no longer apply to your wife. She still needs to wear her hijab and practice regular prayers. If your wife was to follow through her plan, which is not recommended, she will still need to tell her parents the truth. It may be even more hurtful in the long run. Perhaps one of the greatest benefits of her showing her Islam openly is that she will become even keener to call her family to Islam and she will start to look for suitable ways to do that, such as corresponding with them, talking to them, and sending them audiovisual materials on Islam. Perhaps Allaah will guide them to enter Islam, and that will be included in the balance of your good deeds. Thus your wife will be safe from committing those haraam actions of living by their rules, she will have established proof against her family, she will have discharged her responsibilities before Allaah and she will have striven to guide them and save them, because it is not right for her to have the blessing of Islam and deprive her family of it.
Has your wife considered the consequence of her plan in case it did not work out? She could be seperated from you for a long term only to realise that her parents are not willing to revert? In this scenario, you have the seperation, the negative ourcome regarding the conversion AND your wife still has to tell her parents that she is married. Her parents would not be pleased knowing that she had an ulterior motive, kept a secret and did not trust them with the truth. In this case, the chances of them reverting would lessen by a great deal as they would be carrying hurt and negative thoughts.
May Allah Subhanahu Wa Ta'ala guide you and your wife and make this whole matter easy and positive for you. Salaam