The song in question is Loch Lomond,
which goes something like the following:

I'll take the high road
And you'll take the low road
And I'll be in Scotland afore ye
But me and my true love
Will never meet again
On the bonny, bonny banks of Loch Lomond

Here is the complete song....

By yon bonnie banks and by yon bonnie braes,
Where the sun shines bright on Loch Lomon'.


where me and my true love were ever wont to gae
On the bonnie, bonnie banks o' Loch Lomon'.
O ye'll tak' the high road and I'll tak the low road,
An' I'll be in Scotland afore ye;
But me and my true love will never meet again
On the bonnie, bonnie banks o' Loch Lomon'.
'Twas there that we parted in yon shady glen,
On the steep, steep side o' Ben Lomon',
Where in purple hue the Hieland hills we view,
An' the moon comin' out in the gloamin'.
O ye'll tak' the high road and I'll tak the low road,
An' I'll be in Scotland afore ye;
But me and my true love will never meet again
On the bonnie, bonnie banks o' Loch Lomon'.