Here is a link to what I did.
http://www.thorforums.com/forums/f27...olar-5678.html
A few notes if all your camping is out west without shade series panels will save you on wire costs but will lock you into using MPPT for a controller.
Parallel the panels if you camp in a lot of shade and make some portable.
The charge controller isolates the system from the on board converter, and the alternator.
Base the number of panels on 10% of your battery bank aH capacity. For example two 6 volt batteries in series is typically 225 aH there for the panels should produce 22.5 amps in full sun. While you can drop this to 5% it may reduce battery life. Just remember at 10% it will take about 6 hours in full sun with clean panels to reach full charge if you are drawing nothing out of the batteries while charging.
While the rule of thumb is 100 watts of solar per 100aH of battery we have found it is closer to 140 watts and that is extremely conservative in usage.
Pre wired RV's tend to have to small of wires, I replace the 12 awg wires that come with panels with 10 awg. If you have a run that goes over 20 feet plan on going up in size to 8 awg. With 2 100 watt panels on the roof feeding 10 amps to the charge controller my system loss is 0.2volts for a 15 foot run.
With panels in series you can do fine with 12 awg wire for short runs or 10 awg for long runs
On our system the battery monitor doesn't measure current to the cranking battery since I wired the shunt in the house batteries only.