Due lack of bunks the furthest this aircraft can make it is places like Dallas, Houston, Seattle in the west, and Delhi in the east. Nairobi would also be do-able to the south.
Mexico city would probably be just too far, whereas Cancun would be ok (i doubt Cancun will fly from LHR though). California is out, as is further into India, South Africa, South America, and the entire Far East.
The -10 should feature heavily in the USA, especially east-coast, and middle-east. It could also do BGI, BDA etc one day.