The only way to get autorouting and rerouting without an internet connection is by using vector maps. You can get free vector maps for the US from the Census Bureau, but they have limitations. They don't know about one-way roads, for instance, and mapping programs will happily route you the wrong way on an interstate highway, or any other one-way road. I've used Roadmap on the EeePC using these maps, and it works OK, but you have to be very careful with the route you get. It's technically impossible to get any routing from a raster map, which is what Maemo Mapper and most other programs, including Google Maps, use. Any routes have to be done by a server, which uses other means to get the route. Thus it will never be possible to use most free maps for autorouting, and most vector maps with real routing capabilities aren't free, and may never be. If you want actual routing/rerouting on the fly, you have to pay for it.