2002 BF 9.6 camper...2009 BF 25 trailer....2017 BF 10.4 camper...never a concen walking about on roof of any of them....have installed solar panels, reworked roof vents, wash rigs starting on roof first...on my buddies 2002 BF we were both on his roof once tilting solar panels.....both of us over 210lbs each.....only thing I noticed is that my current BF 10.4 with the skylite placed to one side over the table seems to have a bit of flex if I walk right alongside the skylite, so I avoid that.
I should add these were all BF 2500 series .....cannot speak for the BF 1500 series