We have had no problem ever getting good ticket sales departing from Winnipeg. We purchased out 3 tickets for April from NWA and I believe it was about US$450 a person, including taxes and fees, roundtrip. That really isn't such a bad price.
In the past we have also flown United. Also similar good deals.
Granted, there are usually stopovers involved (usually Denver, Minneapolis, or CHicago) but from my experience they have never been more than an hour or too, unless there is a major unforseen delay.
I've gone all over the states (LA, Las Vegas) departing from Winnipeg and never found the flights to be at too horrendous of times or prices. You just gotta look around and find the good deals. Check the airlines websites. THere are good deals just wait for you!
I personally think that with the time constraints, cost of gas, etc. it is not worth it to travel to a different airport. While Grandforks does has an airport, it is not a big one, and fargo and Minneapolis are just a bit too far away. When I go to WDW, I just want to get there NOW, not drive for hours then sit in an unfamiliar airport. That's just my opinion though.
