Actually, they usually don't even need to remove the body panels unless the frame is severely damaged.
When they were straightening the one frame member on mine that was bent after I parked it on top of a van, they didn't have to remove any of the body panels. It even came back into perfect alignment after the repair (they said that was a VERY good indication of the process).
BTW, sorry to hear of your accident. Let us know if we can help.