A history of the song is given in an article here. (Well, actually, I got it from the Google cache here.)

The Penn State University Library has the sheet music.

Lyrics copied from the Olde Webster Archives (click to hear a choir singing it).

THE LAKE SONG, also known as
BY LAKE CHARGOGGAGOGGMANCHAUGGAGOGGCHAUBUNAGUNGAMAUGG
Words and music by Will Heagney, Will Mahoney, and Bert Reed.
Published by Harry Von Tilzer Music Publishing Co. 1935

What a place to see, what a place to be when the summer is here
You can spend all your time at play, blues will soon disappear.
Every day will be one big holiday, you'll be living at ease,
From early morning till late at night, you can do as you please.

When you hear the rippling water, it will set your heart a gogg,
At Lake Char-gogg-agogg-manchaugg-a-gogg-cha-bun-a-gun-ga-maugg
And the rhythm of the bull frogs, with their love-lorn dialogue,
At Lake Char-gogg-agogg-manchaugg-a-gogg-cha-bun-a-gun-ga-maugg.

Oh, there is such a lot to do, you lose all track of time
Nobody knows it's Sunday till they hear the church bells chime.
You can find out where this place is, if you look up your geog,
It's Lake Char-gogg-agogg-manchaugg-agogg-cha-bun-a-gun-ga-maugg.
It's Lake Char-gogg-agogg-manchaugg-agogg-cha-bun-a-gun-ga-maugg.