I have a client who has Sun in 3rd. She retrained as a lawyer on her first Saturn return. Hearing from her, her work as a lawyer revolves around 3rd house matters - contracts, words, communication, writing, etc. She didn't mention whether she does routine travel as part of her work.
When I first thought of Sun in 3rd, I was thinking, Golly, isn't it dull for someone's life to revolve around words and communications? Ironically, my natal Sun rules the 3rd house! When I think more about it, it's pretty amazing actually - the world needs people who are vitalised by words, communication, ideas and thoughts. Imagine a word without gossips, stories, newspapers, news, tabloids, magazines, books, blogs like this, road signs, modes of transportation e.g. cars, buses, bicycles, etc. The world will be chaotic, sadder, less fun, and harder and takes longer to get from point A to B.
Ultimately, the 3rd house is establishing the connections - a news story or sibling, they connect us to the world.
Cosmic Insights for an Even Better Life