I received a copy of "Mr. Moppet's Mailbox" as part of a Goodreads Giveaway and read it to my 3-year-old the day it arrived.
The book presents a simple problem -- Mr. Moppet's Mailbox has broken -- and shows the various absurd ways that Mr. Moppet tries to fix the problem before finally arriving at the solution.
It was totally on my son's level. He was able to follow the story without any confusion, and I could tell he was engaged because he asked questions at the end: What mail did Mr. Moppet get? Was it a love letter from Lady Lucy?
I'm reluctant to say anything critical, since the book is clearly a labor of love for the author, who likely produced it on a shoestring budget, but I suppose it should be mentioned that the illustrations are not the book's strong point. But I think that mattered only to me and not to my son, who was more interested in the story than the quality of the artwork.