You may want to get a good shunt-based battery monitor, like the Victron BMV-712. This will help you see exactly how much capacity you have, how much you are using at any time, etc. It helps you manage your energy usage in many ways.
Note that you should never allow the GC2 batteries to go below 50% SOC (state of charge) or their life expectancy will suffer. The battery monitor helps with this by showing you available capacity only (when the monitor says you are at 0, the batteries have been depleted to 50% SOC).
Given that you are new to TT, I'm not sure how you can know your usage is typical
For example, if you sit at your fridge with the door open while you decide which beverage/snack to select, you let all the cold air out (it will just poor out the bottom) requiring a lot of energy to "re-cool" it.
We're just about in the same boat as you. We've installed the BMV-712 with 2 GC2 batteries. We've converted all our entertainment gizmos to run off of 12V and use a small inverter to run the TV (just like Logan-X, above). We're planning our first trip with this set-up to determine what our power consumption looks like. We'll see