From all the information I've accumulated over the past year+ from this forum, is that the number one first thing to install if your going to do a lot of dry camping is a good battery monitor.
The little one that comes with the trailer just has a scale of L, F, G & C which stands for Low, Fair, Good, and Charging respectively. You'll note there's no concept of Full, Empty, 2/3rds, etc... on that scale. That's because the onboard monitor doesn't know what kind of capacity is left in your battery. It only knows about a point in time measurement (which I believe it does by checking the voltage.) I used to get the scale wrong too until I started hanging around on these forums.
A good battery monitor (the TriMetric name seems to come up alot) is supposed to be essential to getting a good grasp of how many AmpHours you're actually using, how many you have left, and how long you need to recharge to put back what you used.
The next step is to kill as many of those parasitic draws as possible. A good place to start is the sticky thread:
Battery gone in 36h, where to start?
This thread covers a feature in some of the Dometic fridges to combat condensation, but has a tendency to kill batteries. Killing that feature is supposed to save a few Amps draw.
Swapping to all LEDs can reduce your lighting draw for the entire trailer to under what a single bulb used to draw, and putting your radio on a switch can combat the draw used for the radio's memory (at the expense of memorized radio stations.)
Note: These are all just tips I've read from various dry-camping threads, but I haven't actually tested any of them. My DW doesn't dry camp. From what's claimed on here though, some of these guys can go a while by optimizing their rigs for dry camping.