Using solar can work very well. We spent eight days on the North shore of Lake Superior in a shaded camp site and our 185W high voltage panel supplied all our needs and we ended up at the end of the eight days with 64% state of charge in our 150AH AGM Lifeline battery. Our teardrop trailer was designed for solar LED lights computer case fans WAECO 12V refrigerator. High voltage panel(s) produce usable current from sun up to sundown and in shady conditions but do require an MPPT controller.
12V 6V makes no difference it is amp hours which may be easier to get with two 6V.
My suggestion is read http://handybobsolar.wordpress.com/ long but worth it. He has specific reasons for his recommendations that are for the most part very valid.