Well...the good news is that there is a path all the way around the lake so even if the bridge is closed you'll still be able to go back and forth between the resorts. The bad news is, depending on your room location at Pop, it could be a looooonnnggg walk.
We're staying at AoA next June and I'll be sad to not have easy access to Pop if the bridge is closed. Our adult children and spouses usually get rooms at Pop so we're all close to each other and can come and go from the parks together. It would be nice if there was a shuttle van that ran between the two resorts if the bridge is closed....but I'm not expecting that -- it's just a dream.