Skyservice Airlines (not Canada 3000, who went out of business last fall) plans to operate their single A319 from YHZ and YYT to LGW. Off the top of my head, the A319 has a range of somewhere around 6700km. Both YHZ-LGW and YYT-LGW are much shorter than that, YHZ-LGW is about 4500km, YYT-LGW is about 4000km, shorter than YYT-YVR.
coast USA to Hawaii? No. That would be in the 7000-8000km range. West coast to Hawaii should be no problem, as other airlines operate 737's on those routes, I believe.