I use a mapping program called Orux and really like it. It doesn't do voice prompts, though. It does allow you to import gpx routes and has an alarm feature if you stray. It has a few map servers that it links to for maps. One of them does a nice job of ovelaying the road info over topo maps and includes bike routes. You can download maps for offline use. You can also download topo maps on your own from usgs and calibrate and install them using a desktop ap that orux has for free. I also use this ap for making nautical charts. So it doesn't have exactly what you want but is pretty intuitive to use and has good support.