Do the research. Cram as many amps that you can in the space available. The fewer the connections the better also. Pay attention to group sizes e.g. group 27 vs group 31 batterys. Maybe a single battery like a 4D or 8D will work for you.
What type of battery works best for you? Wet cells need to be mounted upright & have ventilation. AGMs can be mounted anywhere anyway. They are sealed & non gassing.
AGMs are popular with boaters for this reason. They are often located under berths. Being a boater at heart I swapped the piddly group 24 12V wet cells for a single 4D AGM in 2010. It is still going as strong as the day installed. We do a fair amount of dry camping.
