Not sure how to do it, but I am sure that it would take some very good body work skills and experience. It can be done. About 7 years about my buddies chevy got really messed up ( as did MANY other cars/houses in the area) by a really bad hail storm that hit with a very severe T-storm. Hail was about the size of baseballs. His insurance did not total out his truck, even though when looking at it, it looked like someone went crazy with a ball-peen hammer ALL over it.
The ins company paid to have the roof, amoung other areas replaced. As I remember the body shop removed his roof either where it met the upper A and B pillars etc or they actually removed the pillars and roof, cant remember. They did do a great job putting it back together and painting and you could not tell that there was a repair. Everything lined up too. They had the truck for about a month to get this and all the other damage repaired on his truck. I would think that it would be hard to do in your drive unless you had ALOT of body work experience etc, but I may be wrong as I have NO body work experience.
Hope this helps and sorry to see your rig in that shape,
J-