This one was in my RV when I first got it:
https://www.amazon.com/RV-Repair-Maintenance-Manual/dp/0934798702It's pretty comprehensive and covers all of the systems, though at a general level. It doesn't have any manufacturer-specific info that you may need for more in-depth repairs. Or, at least my very-old version doesn't. The latest version in the link above has great reviews.
As far as problems, there's going to be problems. You see a lot here because no one comes here just to say "hey - everything's working great!" A motorhome in particular is going to have more issues because you are maintaining a truck/bus and a home. Even on newer ones, there is always something to maintain or repair.
A search on Amazon also came up with a couple of highly-rated books on making the decision to full-time. You might want to check those out too.
