Before you do anything.... check with insurance to see if you are covered for flooding....... if you are just claim....... engines rust inside.... and break very easily if there's water in there and you aren't careful..... the ECU is in the engine bay, i wouldn't be surprised if it has water ingress.... Interiors are NEVER the same after they have been wet, especially with rain/mud, etc..... try and claim before trying anything IMHO!
Otherwise what you said works..... only way to dry the interior is take it all out and dry it out of the car, the floor of the car will rust otherwise as it will hold large amounts in the underlay...... the door panels, etc are not ready to be wet like that........ you will have to replace them most likely
Aaron