The subwoofer does draw some power as it does not have an off switch (some may have it under the dinette seat and it is relatively inaccessible). I installed a switch and leave it off a since a subwoofer seems silly in a trailer, but I'm not 20 years old. The TV antenna booster, if left on, also takes power. And the battery disconnect may not work properly.
The igniters on the fridge, furnace and water heater also take power when in propane mode.
This does not explain the Jeep dead battery so long as the charge line was not hot when the Jeep was off. Have you had the Jeep battery tested? A door may have been enough ajar to cause lights to be on, but you wouldn't know if you didn't notice the door was slightly open and the light wouldn't be on to tell you when the battery died.