It's fairly easy to remove the molding from a door, replace the glass and then reinstall the molding. But it takes careful, slow work.

Evaluate door handing when you replace your old door. Perhaps it makes sense to move your hinges to the opposite side. Glass or panel inserts give the front door a more substantial and designed look.

Part 5 of the father/son 1969 Mustang project shows how to replace the damaged door glass and hardware with new items from National Parts Depot.