I hope Keystone resolves you issue fully, that's some bad looking cracks, and it does make sense the slide might have caused it. I'm really interested in hearing how well they work with you.
Phil P, I just bought a new Montana, took it out last weekend for a tryout and was very pleased, only some very minor issues. In April, we bought a Forest River Blue Ridge 3600RS. In the 6 months I owned it, we got to use it 21 days. Among other numerous issues, slide rollers and brackets on all slides installed in the wrong position, all slides had to be removed or partially removed and rollers and brackets replaced, massive water leak down the inside back wall because the frameless window opening was cut too big, you could actually see daylight above it. My list is much longer than this, but my major issue with Forest River was their casual attitude and lack of caring. They would not extend my warranty, offer me any type of compensation or trade and even balked at paying some of the work even after they authorized it. They also lied to me more than once. My dealer traded with me at his cost because he felt bad about the whole thing, and has been there from day one. All RV manufacturers build some bad ones, but the true measure is how they step up and handle the issues. Good luck with what ever brand you choose, I must say I'm amazed they will give you engineering drawings and electrical drawings, and let someone else look at them, that stuff is usually proprietary.