I'm finally about to set up my very first car PC. However, I'd like to do it with some obsolete crap I have lying around at home. The goal for now is just MP3s & GPS. My technical skills are very high, as I've done other electical car-based projects, and I've got craploads of computer/mobiletech experience. However, I need some innovative ideas about the interface.

I'll go over my general plan first:
- The main PC will be a Xybernaut Mobile Assistant V in a dock (500MHz small form factor). It has one USB port & 1 PC card slot. It will probably run Windows 2000 or XP.
- An Audigy 2 PCMCIA card will go in the PC card slot, with a 3.5" cable to the aux in port on my JVC head unit.
- A 4-port hub will be connected to the USB hub. Connected to the hub will be: GPS receiver, external hard drive, wifi card.
- The PC will be mounted up front, under the radio cluster, so I can reach the power button (one touch suspend). I'd prefer an automatic power on/off, so any ideas here would be appreciated. Maybe there would be some way to use a small UPS... (?)
- The PC will be controlled by an Axim X5 w/wifi card mounted to a Proclip on the dashboard. The Axim will have a Remote Desktop session connected to the PC.
- All power cables will be run to an extension cord connected to an inverter mounted under the seat (or in the glovebox). There will be a master power switch up front, so I can turn everything completely off when I'm not driving the vehicle for a long time.

The Axim is just there as a touchscreen for the PC. However, the main challenge is cramming an MP3/GPS interface onto a 3.5" 240x320 screen. Any ideas on how to make the interface easily usable would be GREATLY appreciated.

I know there are lots of different interfaces for car PCs, but I'd prefer a free one for this build. If there's anything you can think of that will scale to the small Axim screen, I'm all ears. Also, if you see any way I could make the design more efficient, I'd love to hear it. Keep in mind that my ultimate goal for this project was not to have to buy any new stuff.

Thanks!