I have an 06 FK2100 and the only problem I have had is that a pretty big chunk of floor rotted out. Mine rotted from the bottom up. Never seen the area get wet. The fender flair and inner fender was directing water right under the floor and got the insulation wet and rotted the floor.Its fixed and shouldnt happen again.
I have never had a problem with wheel bearings. I have only packed these once real good. Now I just give the easy lube's a couple of pumps at the beginning of each season. I tow heavy and probably way faster than I should sometimes. I dont have the center caps on my wheels and I can check how warm the hubs get when I stop. On a 95 day running 70 they will get a bit warm to the touch but they are all even and seems to be normal temp. Now if I ever feel one warmer than the others I know I am getting a problem. But I never have. In fact, I never have with any trailer I've had.