Because of the phantom loads my battery will run down in 4 or 5 days, just setting in the yard.
Using just the LED lights, water pump for cooking and the toilet and turning off the antenna booster, we will last 3 days max, typically 2 days, before it needs a charge.
If you have solar you can last a bit longer. Unfortunately, only you can determine how long based on how much power you use and how much power you can generate. I have a single 100 amp-hour battery and no charging method except my Tow Vehicle.
Awning, long showers, slide out, exhaust fans, furnace blower all work but shorten the battery time. My microwave, Television, Air Conditioner and other 120 volt items do not work.
Like any special use trailer application, non-hookup camping requires adapting your trailer to the expected conditions. Most Trailer leave the manufacturer intended for camping with electric power.