LinuxICE is a distribution designed specifically for carpc's. Hopefully a new version is coming out soon (ask Kev000). Benefits are the very simple front end that you are after. The reason I haven't jumped on board is because I can't get the right screen resolution or OBD2 software to work.
Moblin is a super-light, fast booting distro we have been keeping our eyes on. Works only on intel boards (like yours), but is early in development. Something really cool about watching it boot in 10 seconds though.
Those are the distro's I have been using/watching right now. I can't comment too much about GPS becuase I don't use it.