First Time Going Dry Camping (Need Battery to work)

We didn't use our camper from November to March and unfortunately, I never disconnected the battery. Also, I didn't get a chance to take a reading with the shore power connected.

Is the Auto Reset Circuit Breaker hard to replace? I noticed that the battery cables go to the front of the camper frame and are secured to this small two-bolt terminal that has a red boot that covers it. Does that have anything to do with my problem?

Thanks again for all the help!