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 won't 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'