If our GPS doesn't suggest a route I want to use I either turn off the navigation or ignore the turn by turn directions and drive using the route I want. Eventually I will get to a point along the route that the GPS agrees with and I can then use the turn by turn directions to get the rest of the way to the destination.
Another way of saying this is that if I know the route I want, I don't need the GPS to guide me.
You can also use the Trip Planner function on the 760 to set up a planned route with via points along the way, but the GPS will still take you the way it wants between the via points.