journaling , illustrations, add a new character to the story, make a new ending, draw a new cover, write themselves into the story
we have a reading journal that we use. for example this week a decodable story was a about a cat in a tree that only comes down for cat food... we wrote on the board "Jan's cat came down for the cat food. I would come down out of the tree ONLY for _________." We talked about their most favorite foods and that is what they wrote in the _____. At the beginning of the year it is just a blank and then as the year goes on they write more and more and then at the end of the year we have them retell the story in their own words.
So your second could choose any of the above writing choices and the starting 1st can start with the illustrations or the ones like mine above.
have fun and be creative.