I think this is how it should go:
Solar panel -> DC switch -> Controller-> fuse or breaker -> Pos buss -> battery fuse -> battery.
Controller -> Neg buss -> battery.
Hotel loads -> fuse or breaker -> same Pos buss as above.
Hotel loads -> same Neg buss as above.
I wonder how many permanent solar installs are done this way. Mine is. With portable 100W solar this becomes less important.
Avoiding more than one cable per battery stud is important for higher currents. I have 3 cables on some studs - power, voltage sensing to controller, small (VERY small) inverter.
Yes, changing lights to LED is a must for boondocking.
If rig came with thin factory-installed solar wire, AND if you want solar of substantial size, you have to use high-voltage low-current panels. Those panels are typically from 230W and up. 270W is often same physical size as 230W. Array of 2 or 3 big panels in series is easy to wire, regular #10 cable to controller will suffice.
In desert 300-500W solar will keep you afloat without a generator on those days when you don't need A/C.
