If you don't find a battery switch (& I doubt you have one), the fact that lights worked once you plugged it in leaves me to believe there is none. If left unplugged for any length of time (3 or 4 weeks and longer), the battery will go dead due to parasitic draws (ie; carbon monoxide detector, digital thermostat etc.).
When I stored our TT I used to disconnect the positive battery terminal and if winter storage, I removed the battery and kept it in the garage on a trickle charger.
__________________
"PT Crew Members Since 9/2010"
2011 RAM 2500 HD 6.7L CTD Crew
2014 Prime Time Sanibel 3250