Popped rivets often indicate significant problems. Dents can often be pushed out but once aluminum stretches it stays stretched. Creases won't go away either.
What I'd worry about is the ribs getting bent. Does the inside show evidence of the impact?
To see some dents, check out Dave's trailer
We are trying to figure out how to get a new rib shipped in as one was broken. The others can be 'adjusted' to somewhere near where they should be. The front roadside dent cleaned up pretty well except for the gash near the bottom. The front top dents also pushed out fairly well.
I guess a lot just depends upon how perfect you want the result to be.