Everybody I know plays it in C, but he wanted it in G, so here is what I sent him--feel free to correct, as I am not a "chorder":
Band Played on is harder, and I am not sure I have it all right. Ragtime does some weird things, so go slow, and play with somebody who really knows the melody for a while. Here is the whole thing, starting with verses: (A lot of people only play the chorus)
In G, 4/4 time:
G C7 C D G(hall)
G C7 C C A (ball)
Em G Em D7 F#
G(Casey) C F#m (change to 3/4 time), bridge to Chorus:
D D D7 Chorus:
G D7 G(band) D7(loaded) G7(nearly)
C7(exploded) Am(poor) Cm(with alarm)
Emdim(girl) G Em A7 D7 A
These are close enough to get you started I think. I did check out a couple other keys for "Band" and none of them are all EZ chords because of the accidentals in the melody line.