I vote against NG/propane lighting. Read an article recently that said it left a dull film on everything that was a pain to clean off. Sorry, don't remember source.
If you need liquid fuel lighting, try an Alladin lamp (~60W bulb equivalent). Lots of light, but also lots of heat. I have two always ready to go, plus a couple of #2 flat-wick kerosene lamps (~25W bulb equivalent). I burn Klean Heat in both (~$11/gal at Home Depot).
I like the solar/battery/light idea. Here is one man's solution to the solar panels, battery, inverter, lighting problem.
"Case Study - Sizing a system for a pop-up camper trailer"
http://www.otherpower.com/popup.htmlIn above, the author uses an inverter and compact florescent lamps (CFLs). However, you might be able to find 12v LED bulbs and save the expense of the inverter. (Don't use 12v filament bulbs. Too much current draw.) Search for "bright 12v LED light"
Ignorance speaking here, so be cautioned. If the 12v LED bulbs don't exist, or are too expensive, you could make your own. How? I believe it requires 3v to light a white-light LED die. So 4 of them, wired in series should run off of 12v. (You may need a resistor to drop the current to be correct for the LED string.) Gang as many 4-LED strings together as needed to get the brightness you want.
Another idea. I was recently looking for some bright LED backup lights for my truck. They do exist, so maybe one (or a few) of those would do what you need. Seem to recall they were ~$20/each. (I'm sure they are doing what above idea suggests: wire 3v LED dies in series to work off 12v. Haven't ordered them yet so don't know how well they work.
http://www.superbrightleds.com/cat/truck-lights-lamps/However, the inverter idea would let you use small appliances: radio, small microwave, etc. Really, the small microwave can be used (according to above author) because it is only used for a few minutes a day.
Seem to recall reading you fished with a trolling motor/battery, so you are half way there. Just need a solar panel and some 12v LED lights. Could wire your trailer from the battery with extension cords and pull switches as an expedient. Would need to watch extension cord polarity and length.