Dash cover or dash cap for a '69 Barracuda?

No its not easy to R&R a dash pad. That rally panel is more difficult than others since it encompasses the climate controls and radio. It's somewhat fragile too. I've always recommended this... pull it once. do everything you can do while in there. Put it back and be done with it for years to come.
Now to suggest your method to the madness... Buy the shell type cap. Keep its shipper/box. Lay it in place without or with minimal silicone adhesive.
When you are prepared to renew from the glove box cardboard liner to the wiper pivot seals,,, geter done. At some point you can resell that cap.