The standard answer here would be "go to pprune.com" for some good answers.

This doesn't exactly cover ALL the deets, but it's a fairly decent place to start;

Pilot Jobs Network - for students of pilot schools and experienced airline pilots

In the U.S. at most "regionals", that's the case. However, when I was in LAX I could do YVR-LAX-MZT. Any of the COEX hubs you can do say YYZ-IAH-GDL, or the reverse. Any other combinations of Mexico and Canada as well.