Android Application best routes

an app that saves your home and work/school details. point a = home and point b = work (or vice-versa). Then the user selects up to three destinations that he'd like to stop at on his way to work or home. The destinations are selected from a dropdown menu (examples are Pharmacy, Grocery Store, Coffee Shop, Clothing Store..etc). The app then uses google maps to find the most efficient route from point a to point b including the stopovers that the user stated. The app will give them a choice of which route to take and will state how many miles were saved from the alternate routes. essentially once the user clicks "route" the app will search google maps for the selected destinations and pick the fastest route. it will drop down balloons where the locations are too. there will also be a way to save favorite locations so that the app can automatically choose these in the future. if need more information please tell me.