I've already sketched out the major Commonwealth SST routes. One going from London to Gibraltar, Cairo, Aden, Madras, Singapore, branching to Hong Kong or Darwin then across the Australian outback to Sydney. Another London to Toronto, across the Canadian Arctic to Vancouver, Fiji, Auckland and Sydney. A final one from London to Belize, then along the South American Pacific coast to Santiago.
Keeps the aircraft over the ocean or Commonwealth controlled sparsely inhabited territory to avoid the sonic boom issues