Your generator has two separate sets of windings that go through 2  circuit breakers on the side of the generator.

The wires from your generator will terminate in a handy box, such as is shown in the picture. There will be 2 black wires, 2 white wires and 1 green wire in the box. 1 black and 1 white wire go to the rear AC. With the shore power unplugged and the generator off, remove the wire nut from one black wire. Make sure the wires are not touching any thing and start the generator. Now go inside and see if the rear AC works. Now do the same with the white wires. Once you have established which 2 wires go to the AC, you can proceed with the modifications. The 2 selected wires from the generator will connect to the 20-amp duplex, along with a jumper wire from the green wire. The remaining wires that go to the AC will be spliced to a 12 gauge SO cord and run through a cord bushing to the out side of the of the handy box. Add your plug to the SO cord and you are now ready to plug in to the duplex to restore normal operation.