How can I convince my father to approve the engagement to a young man he does not know, and who lives in another state?

If a young man is pleasing in his religious commitment and character, he should not be rejected merely due to a difference in states [regions/countries]. The father should be convinced to accept him through the mediation of respected individuals, as the Prophet, peace and blessings be upon him, said: "If someone whose character and religious commitment you are pleased with comes to you [seeking marriage for your daughter], then marry her to him. If you do not do so, there will be tribulation on earth and widespread corruption." The father's opinion must be considered if he refuses for a legitimate Sharia-compliant reason, along with the importance of performing Istikhara (prayer for guidance), and repenting from any illicit relationship with the young man before the legitimate Sharia-compliant marriage.