I don’t advise the alternative. Someone once cut a hole in the cowl above the area and finished by welding it back in place. Bad plan. So much to go wrong.
From experience, the connectors those lines use to the evaporator are soft copper and the fittings are super tight flared with inertia from 50 years. If you can’t get two proper wrenches in place with fair elbow room and those copper connectors twist you’re looking at a new evaporator. Dashboard removal is inevitable.
Oh, and there’s also the cork tape you have to remove by hand before you can do anything. Enjoy!