As you noted, this is a common complaint. I have replaced the thinner angle iron brackets with heavier "C" channel on our TT and it reduced the bowing significantly.
Regarding cancelling your upcoming trip - can you travel there with the FW tank empty and then get water at the campground? There isn't much risk of the tank dropping our if the trailer is just sitting at a campsite. Bouncing around on the road - well that's another matter.
I just want to be outside!!!
'17 Salem Cruise Lite 210RBXL
'11 F150 5.0
Two shedding mutts