The popping noise very likely was from over filling the tank or a blocked vent pipe/over flow outlet,high pressure not allowing air to escape as quick as fill?What relationship do the bumper bracket and stabilizer leg have,as in attachment location to frame.Did fw tank brace twist frame components when it failed,as it surely did,when tank cracked.So after you noticed you had a problem you camped for 4 days,probably bending more frame and components that were bent or over stressed.Who knows except you what happened and how,good luck fixing it.
Did you notice a problem with the door when you heard the original popping etc.doesn't sound like it all occurred at the same time,traveling with the damaged full water tank likely created more damage and the load on the bumper,didn't help the matter.Fix it and get something more substantial.