James F. Hanley's composition is a classic example of American popular music from the 1920s. Its charm lies in the simplicity of the melody and its evocative harmonic resolution.
Pay close attention to the phrasing of the long, lyrical lines.
Comparable difficulty and character — good candidates for what to learn next.
Big Boy is rated Henle level 3 of 9 — late beginner repertoire, roughly ABRSM grades 4–5. In the RCM system it corresponds to about level 3.
You should be comfortable at Henle level 3 — meaning you can already play level 2–3 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
A typical performance of Big Boy lasts about 3 minutes.
Big Boy is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.
Pieces at a comparable difficulty and character include Für Elise by Ludwig van Beethoven, Berceuse by Rudolf Friml, Albumblatt by Richard Wagner — see the full similar-pieces list on this page.