Plugging into the 50 amp breaker means if there is something wrong it has to trip a 50 amp breaker instead of a 30 amp breaker. If the 30 amp is available plug in there. Of course, the power center in your trailer has breakers and fuses that are rated at 30 amps or below, so if something goes wrong inside the trailer they will trip off first.
Model X19H Expandable
GMC Sierra Pick up
Been a camper since I was a kid, and that was a long time ago :)
From pup tents with no floors, to tents with floors and flies, to a pop up, to the expandable.