Krissy: I managed to find an advertisement for it on the Web, which reproduced the first page. Here it is as far as that goes:

All Aboard for Blanket Bay
Words by Andrew B. Sterling
Music by Harry von Tilzer
Copyright 1910

There's a ship sails away
At the close of each day,
Sails away to the land of dreams.
Mamma's little Boy Blue
Is the captain and crew
Of this wonderful ship
Called The White Pillow Slip.
When the day's play is o'er,
And the toys on the floor
Cast aside by a little brown hand,
Mamma hugs him up tight,
Papa whispers "Goodnight,
Little sailor boy, sail into sweet slumberland."

All aboard for Blanket Bay.
Won't come back till the break of day.
Roll him round in his little white sheet
Till you can't see his little bare feet.
Then you tuck him up in his...

I remember the rest as

...nice clean bed.
Ship ahoy, little sleepyhead.
Bless Mommy and Daddy and sail away.
All aboard for Blanket Bay.

My mother sang it too. It was a point of perversity for me & my brother to scramble to get our feet out from under the covers during the line "So you can't see his little bare feet" and to insert "and Joey and Jonny" after "Bless Mommy and Daddy".

Another lullaby based on the same metaphor is in the Pankakes' book:

Sail, Baby, Sail

Words by Alice C. D. Riley
1899

Baby's boat the silver moon
Sailing in the sky,
Sailing o'er the sea of sleep
While the clouds float by.

    Sail, baby, sail
    Out upon that sea,
    Only don't forget to sail
    Back again to me.

Baby's fishing for a dream,
Fishing near and far,
Her line a silver moonbeam is,
Her bait a silver star.

    Sail, baby, sail...