Tarheel,
Once again we are up against the frustrating lack of wiring diagrams for the GS coach line-up! I think that every AC outlet served by the left power center (in the wall under the refrigerator in my 40-C) would be from the inverter leg. It is possible that the loads protected in the middle power center might not be sourced from the inverter, such as the air conditioners, the basement freezer, the washer and dryer, the ac element of the water heater, etc. There is an outlet listed in this group, which is the bedroom recepticle -- might be the one on the frame of the bed itself...
Did you test that one?
I glanced at the Onan Energy Command EC-30W manual on-line at
http://www.cumminsonan.com/www/pdf/rv/e ... ual-en.pdf
and it is an interesting accessory, be sure to let the forum know how it works out when you get it working, thanks!
Chuck