Rust

Two big rust spots on back bumper. Looked underneath and half the bracket that supports the hitch is gone. Rusted out. Lots of other rust underneath.10 year old RV I bought new. I park it on gravel.I am going to look for a welding shop to do some work then maybe see if can get underneath sandblasted and rust coated or Use a drill with a wire wheel.
Any suggestions on getting the rust off and coating are welcome.