I asked Sunline for a wiring diagram on my 2004 T2499 which they sent me. Hutch connected with Sarah and had it posted in the files section. Here it is. http://www.sunlineclub.com/docs/2499wiring.pdf
There is the 120 VAC and the 12 VDC circuits.
Now to your questions on overloading. At home, at least on new homes following NEC rules, the kitchen has several 20 amp circuits as it is a high power area.
However our 30 amp campers are not quite wired that way. In 2004, the T2499 had 4 basic circuits to split up the loads. Each high power pre wired camper device was on itís separate circuit to help not overload each other. You can see them on the wiring diagram. This is why the microwave and HWH can be on at once for example.
The AC unit while it is separate, if you have the HWH on electric, the fridge on electric, attempt the microwave on hi, this will be a problem.
To help prevent from overloading, all you can draw is 30 amps as all of the camper runs thru the one main 30 amp breaker. How ever you add up to the 30 amps will trip it.
Sunline did a good job of splitting up the on board 120 VAC draw for what they had to work with. And they even ran 2 receptacle circuits for 2 sides of the camper.
The galley receptacle, the one next to the sink, is on itís own 15 amp breaker. Check that yours wired this way by using a test lamp and switching on/off the breakers to make sure it is by itself.
The rear wall receptacle by the table, has on several others items but separate from the galley.
If you put the stove cover down and put your electric griddle to run on the galley plug this should be OK providing you are not using a lot of other 120VAC items.
Basically putting it, anything that creates heat that you plug in or turn on, hair dryer, toaster, ele coffee pot, ele fry pan, portable electric heater, is one at a time.
Here is why. 30 amp supply on 120VAC is 30x120 = 3,600 watts available. How ever you add up power draw, if it exceeds 3,600 watts fairly soon the main breaker will trip. If you are on 115 VAC that is 30 x 115 = 3,450 watts available which is slightly worse.
Basically if you have the HWH on electric, it is 1,400 watts all on itís own. Then plug in a 1,500 watt electric space heater running on hi, that is 2,900 watts all by itself. While the actual amp draw may be slightly less as they are rated full loads, itís and easy way to count watts.
Also to keep in mind, the power converter is on all the time. It is drawing power, pretty good if the battery charging is on high, and even if the battery is topped off, it still draws power just sitting there.
During winter I run a seperate 120 lead cord into the camper jsut to dedicate to the portable electric heater. Then the toaster etc can run and no problems.
Hope this helps