At Trial Mountain, the last corner - going counter clockwise - has a "ramp' that is the side of the hill. Flat out in fifth and nail it, hang on, and watch replay. If you go good enough, you can smack the bridge...Dukes of Hazzard kind of stuff...
That is the best launching pad I have found so far. There might be a good one at Seattle, but probably not as good as Trial Mountain....