removing dash from a 69 Dart

If it's just the radio opening, that can be done without removing the interstructure but you'll need to pull the radio, ash tray, heater/A/C control, and maybe the cluster depending on how close it is to the repair area. If you're pulling the windshield anyway, wait until then and do all your metal repairs at the same time. Chances are there is some rust around the opening there somewhere! Check on the gasket availabiliy before you cut it. It might be cheaper to save the gasket (if it's good) and buy a new windshield.