Being a long time RVer, I would really suggest you reconsider what Bob said. Having the generator is great, but having a 12V deep cycle RV/Marine house battery to run the lighting that is charged through a DC converter whenever the generator is running is not a bad way to go. It gives you a lot of advantages like having light to load the trailer the night before without having to run the generator. There are a lot of RV items available the run on 12V that you might want to consider installing also, especially in a trailer. 120V house fixtures are not always the best way to go with a trailer. The 12VDC items are made to handle the vibrations and shocks that come with a trailer. House fixtures are not.
Also, if the trailer GVW will be at or over 3500 lbs, trailer brakes will be required in most states and that will also require a 12V house battery if they are electric. The disconnect pin gets pulled if the trailer comes loose and the battery has to apply the electric brakes to stop the trailer. Depending on what you tow with, even if you are only at 2000 lbs, you might want to consider electric brakes on the trailer. I can tell you the trailer brakes have saved me a time or two. I wouldn't want to tow anything over about 2000 - 2500 lbs without them.
Just some food for thought, if you haven't gone over all that before.