小説 ミラーさん -みんなの日本語初級シリーズ-

It's a very good book if you're only looking to read something for practice, but the story itself is, as expected, a bit bland. Whatever good is in the story is just nostalgia from doing the textbook for me.

It does have some N4 grammar and kanji, just finishing Minna 1 you will understand but not fully, but it's still highly readable and the grammar you don't know you might still understand from context.

Highly recommended read if you finished the MNN 1 textbook and are starting on 2.