Welcome to the forum and irv2.
Your
house batteries maybe located inside your engine hood down in front of radiator along with the chassis battery. Very difficult to service and if you need new batteries I would get two AGM's at Sam's and save some work for yourself.
The fuse panel under bed may have your 12 volt fusing and the load 120 volt circuits for fridge, Micro, TV, AC, HWH.
As has been said the manuals start 1999, wiring and fusing maybe found in the old Owners Guide at the end of it that may help even your coach.
In
QT's 1 & 2 there is some old battery pictures I have posted and some other info that maybe helpful for you.
You may need some help working on batteries and the link should help you if you only have a starter battery like in link, you do need house batteries to supply all the control boards in your appliances, plus you will fine info for them in the links below in my signature.
Take your time and when working on batteries always disconnect negative cable first and reconnect it last, so you do not blow fuses or circuit boards.
You can also use a
link like this to maybe find information in search for what your looking for.
Good luck and enjoy your new adventure.