What is the best way to remove a bad dent from the roof of my car?

I have an old Mercedes 240D that a tree fell on. It made a pretty bad dent on the roof near the corner of the sunroof, which means I can’t get to the underside of the metal to hammer it out. There is also a pretty good wrinkle right near the top of the windshield. Being as the car is a 1978, I am loathe to remove the headliner for fear of not being able to replace it. Money is in quite short supply so I am going to give it a go myself to see if I can do it. I am also considering doing a sunroof delete and just welding it up and then forgo any worry about leakage. But sunroofs are so cool and I bought all the gaskets. I will worry about the one near the sunroof, and get to the one near the windshield once I pull the windshield out. Thanks for your help.