You need to place the basemap objects on their own locked layer so that you don't bump them while you're working on your route.
The images from Google Earth may end up skewed because while they're square images, the images are sliced from a globe and the edges will be at an angle in some locations.
The alternative to Google Earth and basemap images is TransDEM. TransDEM uses UTM coordinates and will seamlessly align the images either directly on the baseboards or as separate objects such as basemaps, and will also place the objects on a locked layer for you.