Very Cool and your install looks great! It looks as if we were doing about the same thing. Take a look at the second to last post in this thread...
We plan on using the jack on the front of the our Sony to connect our Sirius satellite radio. We can do without the idiot box (TV), but we gotta have tunes when we camp.
PS - Something else you may want to consider doing is to splice in a 12V
power outlet (from Radio Shack or like store) on to the 12V
power wire going to the radio so you can use a car charger to keep the I-Pod battery charging.