They need to play two summers off site (a la the Bears when they renovated Soldier Field) to more or less gut Wrigley down to the foundation and rebuild it from the clubhouses up. Keep the scoreboard and the outer "shell" of the ballpark, but redo everything on the inside. You could make it look and feel almost exactly the same but with modern amenities. The problem is where do they play? Reinsdorf would probably either refuse to share Comiskey or charge them a ridiculous amount to play there, and there is no other ML sized facility anywhere close by (unless they could figure out how to configure Soldier Field to a usable ballpark).