In our 5.0TA have 3 12v receptacles, one outside by the 120vac, one in the center of the U dinette, and the one right by the door (standard). We use the one by the door for phones and such, the shelf right there makes it convenient. The one at the dinette for the laptop and readers, and the outside one for a fan and to run the little inverter for charging the drill/driver and portable vac. The little inverter fan is kind of noisy so outside works well. So far the 3 work out just fine for us. No extra 120's, way more then we need now.
If you are interested, as far as cabinet lighting, or the 12v for it. We only needed to add lights in the closet and the little cabinet right across from it which we use as a medicine/bath cabinet. The overhead lights don't do much in these 2 locations. There is already 12v in the medicine/bath cabinet for the under mount light so that one's easy. For the closet I ran it from the captain's light on the drivers side of the bed through the overheads (you can just see the passenger side lamp in Alf's picture. For our use the rest of the cabinets are okay with just the overhead lights, so far.
As far as I'm concerned, there is no "good" place for a TV, both sides can't see it very well from the table. An additional one on the middle of the dinette would probably help as we've been using the laptop as a TV and put it right on the table.. I thought I read somewhere that only one cable connector can be driven by the amp, but I'm not sure as I only have one.