Happycarz. Wow indeed the issue was experience by another. Thank you so much for the details and photos. I probably wouldn't have noticed the framing was screwed on like that. This will be a winter time project (Dec-Jan). After the Fass fuel pump install did you experience a improved fuel economy or other benefits?
I will do the same documentation process just incase the Beaver is a slightly different setup. Off the top of head I don't see the cross members under the coach, appears to be sealed bottem.
Again, Thank you Happycarz for the details and photos.