Can't help win manual, but you can by a solar panel and silicone it to the roof to keep batteries charged.
I have found then on line or at half price book stores
If you cant find it online you might be able to find the manual for the component you need info on. also try the rv forums they have lots of info.
Yeah right. This is antique, approaching historic. If not already there. It's hard to find anything under 82, cars, trucks and such. Let alone a travel trailer. You have a tear it apart and fix as you go trailer. Been there , done that.
We have no owners manuals for any vehicle of this type. Sorry