I am just about to start me own car project with a laptop, and am looking into the software I should use.
I tried out autoroute, as i love the maps in this package, unfortunately its gps section is a little lacking, as i guess its more for planning than navigation.
I remembered a bit of software i tried out years ago, and notice its still going, but no mention on this site.
http://www.gpss.co.uk/
I did at one point extract all the detailed maps from autoroute to use with this software, so could do that again. (for the uk, usa maps are free)
Just wondered if anyone had experience with this?