A lot of people everyday solves the problem how to choose the best route (delivering products to supermarkets, encashment, promotional tours, delivering of parcels etc.). Some tourists make such decision too. Total time on moving is taking as optimization criteria in those cases.
Some ways to select optimal routes are described in Wikipedia article “Traveling Salesman Problem”.
In my opinion, it is advisable to enable the option "route planning" in the Bing Maps.
I designed the algorithm which I teach to my students. According to the matrix of durations between places computer calculates the route with the least total duration. User can set the planned durations of stay in the points. By the way, the duration of moving from point A to point B may differ from the duration of moving from point B to point A (for example, because of traffic scheme). In addition, the algorithm takes into account which point is start, which one is finish. User can set the following constraints: to arrive to that place not later than specified time or not before the specified time. All data is described in Excel sheet.
I think it'll be useful to add such algorithm to the Bing Maps instruments. It will make the Bing Maps more popular.
Can the matrix of durations between marked places be formed (automatically) due to Bing Maps instruments?