I would get accustomed to checking my trailer batteries when camping off the power grid and if they get down to around 12.0VDC at the end of the one day/night battery run then you may need bigger batteries. Do some trial runs in your back yard.
It has been my experience to NOT allow my batteries to drop below 12.0VDC before promptly re-charging back up to at least a 90% charge state. This keeps my batteries in a good long life term of good performance.
Of course when adding more batteries then you may have to also increase your on-board converter/charger current size and start doing thing like changing your trailer lights to LEDs and using smart mode charging technology...
It does take some planning to be be successful camping off the power the grid. We found real quick you just can't show up and expect it to work like you want it to. It got dark on us several times around 10PM at night before we got serious about making changes to make it work for the way we like to camp off the power grid.
We do very well using three 12VDC GP24 Interstate deep cycle batteries in parallel giving us around 255AHs with running all the things we want to have ON when camping off the power grid. Then we re-charge our batteries each morning using our 2KW generator and smart mode charging technology to get our batteries back to their 90% charge state so we can successfully do all of this all over again the next day/night run off the batteries.
This is what works great for us. We plan to add some solar panels in the near future to keep us from having to run the 2KW generator as much.
Roy ken