There's not really such a thing as an owners' manual for most towable RVs - especially one that old. You may be able to find PDF manuals for the appliances and other components by going to the manufacturer's web sites with the model numbers (i.e. furnace, refrigerator, stove, AC, etc.). The running gear (chassis, axle, bearings, hubs, etc.) are industry standard and any good trailer shop can work on those parts. You should have the bearings and brakes inspected and, if the tires are over five or six years old, replace them before you tow the RV.
Otherwise, YouTube is your best friend. Folks have put videos out there to step you through almost any scenario imaginable. Bobbo's suggestion of having an experienced person come over and do "boot camp" with is also a great idea.
Rob