The speaker is stuck at home, short of money, and admits to talking about travel more than is probably wise. The opening has a wry, self-aware tone: he knows he is a bit of a bore on the subject, and he knows why. Travel is something he wants but cannot afford.
So he turns to books. Being "busy with writing" suggests he is also reading and working with words, and the phrase "I save my eyes in a book" is a neat double meaning. He keeps his eyes safe and stores them away, but he also rescues them from boredom by sending them somewhere else. The title, "Vicarious", fits this: he experiences journeys secondhand.
The last lines are the quietest and the saddest. He gives his eyes "the life I doubt / I shall find." The mood is gentle and resigned, with a small ache of doubt underneath. Reading is a consolation, but the poem hints that he isn't sure the real thing will ever arrive.