I would look into Netremote, haven't used it personally but it says it can be used with Girder and can make use of Pront remote's CCF remote files..... which if aren't familiar with Pronto is that pda-sized touchscreen remote for home theater use (a very customizable, super-universal remote). But if it can use CCFs then you can design your own control pages and then just learn in the IR codes to use with Girder. I used to program those remotes for a home theater company and with pronto software it's pretty easy to do and the sky's the limit. You can make your own graphics and use them as buttons or whatever. I haven't played with Girder either but if you used it with that then I don't see it being too much to make a few of your own control screens with basic controls for Road Runner (play/stop/pause/ff/rr, switch source, volume, etc...)
I do use Salling Clicker which is another control app and it can use plugins that let you control other programs. So I can use the pocketpc as a mouse pad for my computer, and can use it to control windows media player and winamp.
http://www.salling.com