If I understand correctly, yes you can use the DC output from the generator to charge the battery, and it will produce more current to the battery. BUT you lose the protection of the trailer converter and can over charge the battery and damage it. Doing this for 1hr might not harm it in anyway, but repeatedly doing this could harm the battery.
I am not sure what your camping style is, but I purchased the top rated Trojan 12v battery, of which cost about $175 (the Trojan battery web page has much good information about batteries)... I also replaced all my light bulbs to LED's bulbs. I have the X-139 trailer, so yes, very small. I tested my current draw from the battery with all the lights on before I replaced the bulbs, I was about 5amps. After I was about 0.75amps, so the LED bulbs are very worth their wild. Cost me about $100 to replace all the bulbs.
I spend most of my camping without power, as we stay in National Park campgrounds or in the National Forest Camp grounds...the longest being 10days with no power. Driving to a different place after about 5 days and to be honest we didn't even need to run the generator at all. It is only my wife and I, and we took a shower every other day. It was in the summer so we didn't use the heater either. Basically only the lights and water pump.
If you are conserve your electric you can make a top rated battery last for 3 days easily, most likely longer.
With all that said, i would still carry my generator if I am planning on camping without power for more then 3days, and I just use to generator to charge the battery.