Since the poster specified "best battery" and the probability that his rig will be unattended for a great majority of the year it means using a low loss battery or a solar panel. What was not specified was the amount of shading the rig gets nor the likelyhood of dirt or leaves inadvertently blocking the cells.
For battery alone an AGM will fill the bill. Don't know about anyone else but me shelling out 130 dollars for an ordinary Wal-Mart group 29 battery, hurt. Double the money for a lifeline AGM wasn't as painful.
With a panel, the subject of shade and debris needs pondering.