Ken, how do you do that?
But seriously Lee, the default is actually to take the fastest route which you can change. Nonetheless, you will inevitably find your needing to alter the routes you create - which is one of the big pluses of Streets and Trips. So, you will probably want to take the time necessary to get your wife comfortable with these en-route "Stops". Actually, I wish they were called "Waypoints" rather than "Stops" unless there is real stoppage time involved. Maybe you can get her to buy into that concept. For instance, you could edit the Stop name by inserting the word "Waypoint" in it before whatever S&T names it by using the Rename feature in the Route planner.
Also, you should point out to her that just because S&T calls it a Stop, no allowance for slowing down and starting up again is made on either side of the Stop. Therefore, if you have dragged a waypoint onto an Interstate Highway, it will zoom you right through the Stop at route speed.