Indeed in the abscence of a RISC OS laptop the A9Home would probably make quite a good GPS/Satnav unit.
GPS modules are widely available and even hand held units (with serial port) are available that could be pressed into such use with A9Home. Garmin (and other makes) in addition to proprietary data sequences can be persuaded to spit out NMEA code (basically fairly easy to read ASCII) the task of generating routes, waypoints and maps on the A9 would then be a programming task. The data rates from the units are pretty low (AFAIK 9600 bps, with the co-ordinates updated at approximately 1 second intervals, no need for USB 2 here folks !!!!).