The Chilton's manual is 221 pages. The pages are physically smaller than the shop manual and the amount of info per page is less. It presents most of the same info found in the Dodge shop manual but in a different format and in an abbreviated manner, and it doesn't have the torque tables and isn't quite as in-depth or have the exploded diagrams found in the shop manual.
However, it does have the basic info on the OEM roof air and refrigerator systems with good troubleshooting guides. It also has a very abbreviated section on the body but, nowhere near as in depth as the Eyebrow Winnebago body manual has (also in the club store).
I would honestly say that the Chilton's is a good, basic version but the best references for complete info are a combination of the Dodge Shop Manual, the body manual, and any manuals you can find in our manuals & diagrams section (free to Full and Life Members) which are specific to the stove, fridge, roof a/c, furnace, etc as you have and the operator's manual as well (free to all members).
There really wasn't very much change at all from 74 - 76. The main, noticeable one is that, in 1976, the front window and eyebrow was angled slightly rearward instead of forward. The mechanicals.... very little. I would venture that most of the changes would be increased emmissions related items but, I would present that someone with more experience with the '76 year.