Crossing the boarder into the usa with LMO and getting work permit

Hi,

I'm new to forum and considering going to Canada and wonder if anyone with experience can help me.I am from the U.k and im considering going to Canada(Alberta/Calgary) in the summer to find work.I'm going to be looking for work in hospitality/manufacturing sector for jobs because they are listed under pressure.I phoned the foreign worker helpline and they said i could get a job offer within Canada,wait for the LMO(2-6weeks) then cross the boarder into the U.s and go back into Canada & collect my work permit.They said many people do this,but finding a job is the hard part.Anyone done this before?
Also i keep reading people saying that its hard to find a job online and more chance in finding a job by being there in person.Just wondering if anyone has gone this route and has been successful.

thanks for reading