Be sure to do a careful comparison of the various GPS software applications. They have the same core capabilities, but differ when it comes to things like saving routes ahead of time or using more than one waypoint in a route.
A good starting point is
www.gpspassion.com, although some of the info there is getting kinda old.
I ultimately chose Mapopolis, mostly because it lets you use multiple waypoints to customize a route, then lets you save and retrieve it. But, they've ended all retail sales, so you'll need to look for those features elsewhere.