The OLTL reboot will pick up the story about a year or so after the last episode aired on ABC. During that time, a major storm came through town causing major flooding and much damage. This will explain why the town will look different; all of the sets were dismantled last year.
In theory, they could use this to explain the changes in Pine Valley also, as both shows were set in the same general area in Pennsylvania but I'm not sure where All My Children is going to pick up the story.