Here are some pics of the inside...forgive the poor quality. My trusty digital camera died on me, so I have been taking these with the old digital video camera.
Everything is mounted on small spruce runners. Original design had the main board at the bottom (the unused runners). Unfortunately the 4 pin riser that the wireless USB dongle mounts to is not the most substantial piece of hardware. After soldering the pins to a cable and trying to relocate the dongle I ended up with no signal at all. It worked for a bit but the signal was still poor.
ChumbyLurker advised the use of the USB port for the dongle and the signal difference was HUGE. So I bought a $6.00 4 port hub and relocated the dongle and my added to the number of USB ports. This was also the time that I moved the main board from the bottom to behind the LCD to make room for the USB connection internally. There was a hole in the bottom before.
The power cable was also hacked, so from the back it hooks up with a single RCA connector. This is wired on the inside to a section of the original cord. The speaker was mounted to the back, but I moved it to the front (on more spruce runners) so the entire box resonates with bass. (The Trailer Addict Widget sounds great).