04 Nissan Titan A/V System ?'s

Hope I searched long enough. I have a couple of questions about A/V in the truck, and would appreciate the input. I have a Kenwood HU. Sorry, don't recall the model off hand. It has CD/MP3 and was about 180.00. I have found that to hook sound from A/V source I need to get the Kenwood aux adapter. I have found the HD kit & Software to back up DVD's and games to the slimline PS2. Thanks to this site I found a 12v car lighter power adapter for the PS2. I have no questions regarding the audio end. I plan on replacing the dash bezels with factory replacements to install a 7" LCD in the dash. I have found as another video source a half din DVD player. What other issues might I need to knopw about for the install? Wiring? Shielding? Power? Thanks again, and here are the pictures I could find on the proposed equipment. Sorry in advance for the advertising junk.