I bought my 2010 Honda Insight base model back in December and these forums have really helped me out. I would have never figured out how to change my CVT fluid without the guides on this forum. So I figured I'd give back and chime in with something I've done with mine.
I installed a rear USB charger/Aux port in the back. The USB port is set to charge only while the aux port actually has RCA cables at the end which I connected to the RCA input my radio. The reason I wired in the USB port to charge only is because the radio will always prioritize whatever is plugged into its own USB-in port in the back, and if I switch to another source it won't charge anymore through that port. So the USB port is not plugged into my radio, but a seperate source. For the aux cable on the radio itself up front I turn my radio to "Aux" and if someone wants to plug into the port in the back then I set my radio to "RCA". So essentially the aux port physically on the radio and the aux port in the back are different settings on my radio.
It was actually a very simple install. On the back of the center console is a little plastic piece held on with two screws. I simply removed those two screws, popped the panel off, drilled a hole big enough for the port and put it in. The wires were very easy to run up through the center console to the back of my radio.
In order to make the usb cable "Charge only", I bought an item on ebay that essentially converts from 12v down to 5v/3a and it has two USB ports on it. I tapped into the radio power wire for this and simply plugged the USB plug into this so it would be charge only.
Another benefit of this was that I had a second USB port to work with behind the radio. So what I did was actually plug a USB charging cable for my phone into the second port and ran it through the underside of the radio. I have a single din radio so I have the tiny storage thing under my radio. So when my phone is mounted on the windshield, I can plug it right in and just have a short wire that isn't intrusive cause it just goes right under the radio. If you notice in the aftermarket radio kit, the little storage area under the radio has a tiny hole in the rear for cables to go through.
I can't post links to what I used because I guess you have to have a certain amount of posts to post links, but I'll include pictures of the supplies I used.