The power to the buss bar is probably protected within 3 ' of the batteries with a 12 volt circuit breaker ( depending on cable size ) could be up to 135 amp.
Have you been to this site for Winnebago wiring diagrams , perhaps the best info would be there.
www.winnebagoind.com/diagram/Wiring.htm
Chassis wiring schematics , should be available from Freightliner , by calling the help line with your serial number .
1-800-385-4357 if you don't need the F/L info for this particular install , it will probably come in handy later .