DHC8's on delivery usually go from the factory to Goose Bay or Iqaluit then Keflavik and onto their destination.
Small Boeing's going the other way will route Boeing Field - Honolulu - Majuro - Saipan - destination. That's usually for 73NG's and 757's. Big Boeing's usually fly direct across the Pacific although the SIA B773 (non-ER's) have been going Everett - Incheon - Singapore.
Smaller deliveries like MD80's and 737 Classics coming out of the desert for Europe will often route Bangor - Goose Bay - Keflavik. If they're going to African regions then usually St.John's then Santa Maria and onwards.