The roof had a row of rivets that went all along the perimeter. It also had ribs that went crosswise between every raised roof panel. Those I had laid out with green marker but had forgotten to install. In my haste to add rivets to everything, I mistakenly applied rows of rivets along every green line. Realizing my error, I then had to remove them all which turned out to be easy. I then installed the ribs, one side at a time until the glue cured, and then bent them over and secured the other side. I used wooden toothpicks to hold them down (so I wouldn't leave fingerprints on the soft styrene.) In a couple of minutes, the job was done.
The roofwalks themselves are beautiful etched metal products from Plano Model Products (#194.) There are various styles available and it was easy to find what I needed. They don't come with the support brackets, (though they are available separately), so instead I took some Evergreen #264 c-channel and sliced it into thin pieces. These were then further cut down in height and glued down the center of the car. When cured, I used a file lightly along the top to bring them all into the same plane. I then superglued the roofwalk down, using a variety of metal support brackets to hold down each joint. I could only do a couple at a time. In the future, I will invest in some super glue instant activator.
The only other detailing left to be done is to modify the trucks to add additional springing. After that, the car is off to the paint shop. Decals are on order, so it won't be long now.