These are from his Ebay posting.  I also added a second camera that went on the truck for an additional $110:

The basic kit comes with 16' of high quality cable.  That was enough to get the signal from the back of the truck to the cab.  When I ordered the pinhole camera, I ordered it with 30' of cable.  That was used to get from the back of the trailer to the front of the trailer.  I then ordered an additional 16' of cable to get the 23SS camera signal to the cab of the truck. 

Install in the truck was not hard.  Camera went here:

Had to drill a hole there, but it fit nicely.  Ran the cable up under the frame and into the cab via a grommet for other cables.  No real difficulties.  The monitor went here:

If I had a choice, I would have gotten one of those LCD monitors that mounts over the rear view mirror, but the install for that is MUCH more complicated as it requires getting the cable up to the rear view mirror.  In application, this location works fine.

So, I have the camera in the truck.  Helps out a lot for getting hitched up and seeing any kids behind me.  But for hitching up, the angle does not provide much feedback for when the ball is under the hitch.  I have gotten good at it and usually hit it on the 4th or 5th try :).

There are a lot of cables to stow, but there was plenty of room under the center console.  I also added a switch in the reverse sense line that the camera comes with.  This line automatically powers up the monitor and camera when you go into reverse and then powers it off when you are out of reverse.  You can always manually power the system up as well.  But when you are in reverse, you can only use camera 1, which is the one on my truck.  Not much useful information looking at your hitch when backing up the trailer.  So I added a simple SPST switch in the reverse sense line that disables this feature when towing.

Anyway, here's some pics of the 23SS install.  Might not be the prettiest, but I'll beautify it when the average human height exceeds 10 ft.  Until then, I'm the only one that's seen it and it works.

So, I mounted the camera here:

I just screw it into the facia that is there.  Sturdy enough to hold the camera.  I also sealed it with RV roof goo (rubber roof caulk stuff from the local RV store).  Then I ran the cable back to the refridgerator vent and then down the shaft.  Found a place to enter the camper behind the fridge and then went down through the floor where the LP gas came in.  Then along the frame to the front where I zip tied the connector to the 7 pin RV cable.

The camera connector gets plugged into the male version that I zip tied to the RV connector on the truck.  Not the most elegant, but it works for now.

I used a lot of the RV rubber goo to hold the cable in place on the roof.  Had a lot of suggestions from the RV place and this one seemed the easiest to try first.  After our 1600 mile trip, it's still there and solid.  Probably be that way until I sell the camper.

That's the quick and dirty for now.  I'll clean this up later.

UPDATE:

We sold the 23SS and bought a 2701SS.  First thing I added was a rear view camera just like this one.  Here are some pics:

This install was different in that I ran the cable along the side of the trailer behind the ladder.  Used some of that plastic cable hiding stuff from Lowes. 

The second channel running along the side behind the ladder is what holds the camera cable.

I also ordered the most excellent trailer connector the interceptinc now offers as part of their auctions:

This is heavy duty.  The original connector I was using with the 23SS was getting a bit weathered and this should take care of that.  I mounted the plug on the trailer under the batteries.  That will stay connected all the time.  The one on the truck is on the right side (passenger side).  This won't ever wear out.

I also added backup lights to the back of the trailer.  Simple 55 watt halogen fog lamps from AutoZone for $16.  Ran a wire back from the 7 pin wiring which was conveniently located in a junction box at the front of the trailer.  Grounded the fog lamps to the bumper and ran one 12 ga wire up to the junction box.  Now I can see at night really well.

I gotta tell ya, after towing a 31 ft trailer without the camera and then with the camera, I am spoiled.  My McKesh mirrors aren't quite wide enough to see the first 40-50 ft behind the trailer.  The camera fills in nicely.