Praise be to Allah.
The saheeh Sunnah indicates that it is not permissible for a woman to travel without a mahram. This includes both long trips and short trips, according to the majority of scholars. Everything that is called travelling is forbidden for a woman unless she has a mahram with her.
Al-Bukhaari (1792) and Muslim (2391) narrated that Ibn ‘Abbaas (may Allaah be pleased with him) said: The Prophet (peace and blessings of Allaah be upon him) said: ‘No woman should travel except with a Mahram, and no man should enter upon a woman unless her Mahram is with her.’ A man said, ‘O Messenger of Allaah, I want to go out with such-and-such an army and my wife wants to go to Hajj.’ He said, ‘Go to Hajj with her.’”
Al-Nawawi (may Allaah have mercy on him)said in Sharh Saheeh Muslim, explaining that travel here does not refer to a specific distance:
Everything that is called travelling, it is forbidden for a woman to do without her husband or a mahram, whether it is three days, two days or one day, or anything else, because of the hadeeth of Ibn ‘Abbaas, according to which the Prophet (peace and blessings of Allaah be upon him) said: “No woman should travel without a mahram.” This includes everything that is called travel. And Allaah knows best.
And it says in Fataawa al-Lajnah al-Daa’imah (17/339): It is haraam for a woman to travel without a mahram in all cases, whether the journey is long or short. End quote.
Based on this, if this distance is regarded by people in your country as travelling, then it is not permissible for you to travel without a mahram. But you will be rewarded for your intention, in sha Allaah, and you can maintain ties with your uncle by telephone, and that will be sufficient in sha Allaah.
And Allaah knows best.