We flew out of Dorval once, out of Rochester once, and the last time we drove from Ottawa down to Philadelphia because the the tickets were SO much cheaper than anything available from the nearer airports. We were already very familiar with the drive from Ottawa to Philadelphia so it didn't bother us traveling that far. On the way down we stayed overnight at Syracuse and shopped at Carousel Mall, on the way back we drove directly home from Philly.
My approach in booking all of the above trips was, once the dates were fixed according to the family's various schedules (school/work/etc.) I started checking expedia almost every day, looking at ticket prices from all of the airports within one day's drive including YOW, YUL, SYR, BUF, Binghamton, Scranton, Burlington, Albany, etc. After a few weeks of getting a feel for the prices, but still over 1 month from the departure date, I would book the flight and then start looking into parking lots, airport hotels, etc.
We never had problems with cancelled flights, or having really bad connections (Pearson!) or flying at terrible times of the day/night.