Thanks in advance for any suggestions.

I have a 2003 Denali (non-XL) SUV.

The exterior driver's side door handle loosely clanks back and forth when pulled to open the door as if whatever interior spring or lever mechanism it was attached inside the door that engaged the lock, and opened the door, has come loose, or become detached.

There is a rattling inside the driver's side door door when I drive that would seem to indicate something has come loose. The inside door handle works fine as do the electrical control of the door mechanism so the actual lock assembly appears to be fully operational.

Is this likely to be an expensive fix? Is this a job for the pros or something I would tackle myself with patience. Is it a big job to take the door panel off a Denali? I'm handy, but I'm not crazy.