Proper Interface of 12V from truck, 12V to RV battery, 12V to fuse box

[mspaeder]

2016 Flagstaff Superlite (fifth wheel)

Which is the proper wiring? (Option 1 or Option 2)

Option 1:
12 gauge charging lead from truck joins 8 gauge lead to RV battery in junction box behind pin box, and then lead goes to manual breaker, and then after manual breaker 8 gauge lead goes to fuse box

OR

Option 2:
12 gauge charging lead from truck joins 8 gauge lead to fuse box in junction box behind pin box, and then lead goes to manual breaker, and then after manual breaker 8 gauge lead goes to RV battery

Option 1 seems more logical to me (in order to put a manual breaker between the truck charging lead and the fuse box), but my RV was wired with Option 2. I've been having various 12V issues, and I'm trying to determine whether the RV was miswired.

Thanks in advance.

Matt