We also dry camp without a generator and also have two 6-volt batteries. When we are in conserve mode, we can camp for about 7 days without the batteries discharging to below 50%. For us that is about 18 AH per day. LED lights & no furnace use. First thing I did was to get an understanding of my 12-volt system and how much juice each appliance used.
When I really want to stretch the length of stay, I will keep the truck running while plugged in and drop the landing gear and open the slide before I disconnect the cord from the truck. This style of camping works well for us because we will spend most all of our time outside (including cooking) and only use the rig for the bathroom and sleeping.