We very regularly dry camp for 3 nights at a time with 2 typical 12V batteries on our rig. This includes running the furnace at night and in the mornings (down to the 40's overnight). The water pump gets normal use, including 4 showers.
The only time we had big issues was when one battery cell went bad and we truly *needed* to run our genny during the day to get us through to the next morning.
With the year of your TT, I suspect you have LED bulbs. If not, make that change. Also I have lights in my basement that can be accidentally tripped, and that would increase my battery drain (and not be noticed for hours/days). I've also accidentally left my porch light on by mistake.
Good luck on the troubleshooting, it's worth it to get the bugs worked out.