I did the same to mine. I found the 12v
wires in the front cabinet, and holes ready for speakers at each end of that cabinet. I installed a couple 6x9s stolen out of my truck in the holes, and a nice Alpine in a homemade box hooked into the 12v
, and I've been enjoying it for the last couple years. The mounting box has a big switch for turning the power on and off to the radio, but the memory line is hooked up to 12v
also so I don't lose my settings.
There is also an antenna on the trailer already, and I had to drill a small hole in the bottom of the cabinet to bring that antenna up into the area where the radio is. I plugged it into the radio and it worked on the first try (I think I needed a radio shack adapter to do it). You get lousy reception without an exterior antenna.
One really nice feature was we used a car stereo with an aux out connector, so I can plug my iPod or laptop into it and have quality sound, which is especially nice for when we're watching cable or DVDs on the laptop.