They are both very unique and take the viewer in the peaceful Japanese countryside. Both deal with the old Japanese culture but in different ways. While Yuujinchou is more supernatural about Natsume dealing with the youkai, Lamp is just about one ordinary man who learned that nothing will last forever and one has to change sometimes (the westernization of Japan).
Both share this peaceful feel and the style is somehow similar. The main character is voiced also by the same actor.
Both are somehow dealing with the traditional Japanese culture. Ojiisan no Lamp really reminded me Mr. Miyazaki's style where he focuses on the life around and the thoughts of people and their ideas and visions of the world. Both anime raise up emotions even though there is not anything heartbreaking on the first sight and both evoke this lovely feeling of peace in the viewer's heart.
Both anime focus more on the atmosphere than the story. They're the kind of anime that make you think about things. Ojii-san no Lamp is a short movie/single episode about dealing with the change that comes with time. A recurring theme in Kino no Tabi is how the world is always changing.