For me, there is really not much in the way of the RV manual worth anything. My manual is a generic manual covering Class A diesel, Class A gas, and Class C coaches. Therefore, most of the illustrations are not even applicable, and the information is generic at best.
In fact, the title of the manual says "Class A & C Owner's Manual"
For the one or two pages that have useful information, I scanned them into a pdf.
Shortly after I bought the coach, I went online and downloaded all of the manuals I could in pdf from the various manufacturers. If could not find a manual in pdf, I scanned in the paper manual to pdf, and if I found a pdf on-line that I did not have in paper, I printed it out.
This includes the Four Winds 2 page brochure, which oddly enough has more valueable information in it than the owner's manual (it has dimensions, tank capacities, etc. for my specific model).
And any time I make a modification, add/replace different components, trace wiring, figure out something, or reverse engineer anything, I also scan those items into a pdf and print them to paper.
When I am done, I have two complete sets of manuals; one pdf and one paper.
For the paper copy, I bought a document case, like this one:
I leave this one in my office.
I put a copy of the pdf version on my smart phone with pdf reader. I take this with me when camping, so I have a portable version with me without having to bother with a cumbersome stack of paper documents.
On one hand, it'd be nice that Thor (and other manufacturers) had a complete set of documents, but on the other hand, most RV'ers modify their rigs to at least some extent, and over time replace components with a different model or brand. This makes any document set the manufacturer created outdated anyway. So in a sense, the documentation set is continuously changing.
It would have been nice to have a better document base to start with, but really, things like electrical, plumbing, structural, etc. are not normally part of many owner's manuals anyway. When I had boats, some manuals were not much more than what Thor provides.
However, when I owned a Carver, it came with a binder with dimensional drawings, structural members, parts listings, electrical, plumbing, HVAC drawings, carpet layouts - you name it. That manual was golden, but unfortunately, it is an exception (for both boats and RVs) rather than the norm.
You can sometimes get this data from Thor for the asking, but it might not have the detail you want - but it usually helps.
Also, I have downloaded all of the electrical and mechanical data from Ford, so I have a set of chassis builder documents.
Fortunately, Ford has a "bodybuilder" website which includes both E-Series and F-53 chassis. This is documentation for the aftermarket chassis builders, but it might be valuable for those "advanced" RV tinkerers.
https://www.fleet.ford.com/truckbbas...bodybuild.html
So what I am saying is you can become your own document writer. Then when someone on a forum has a question - you may have the answer.