interstate battery bites the dust in two years

If you leave your trailer in a boondocks location. Solar panel might be a good investment. Would save you from hauling the battery back to charge.

You can get a deep cycle battery at Walmart. A marine battery offen is a combo of a start and deep cycle. A deep cycle will have thicker plates and will take more cycles of charge/discharged.

You do need to disconnect the terminals or install a battery cutoff switch when you let it sit. Parasitic drains will discharge a battery in a week.