Urgent!!!!

I wonder what it would cost to have a new headliner installed at an auto interior place , anybody out there have it done ??
I noticed that mine has separated from the back glass some this summer----------
I had a 69 Valiant done last year. A shop who I know the owner well for a couple decades. We took the old one out and prepped the roof. They had the glass taken out- which is an issue because no one wants to do it in case it cracks. I believe the glass guy walked after he had trouble getting it back together. The shop finished it up and it came out really nice. It was supposed to take a week- took two weeks!
All said- I have $7-800 into it.
I have another car now that we are going to try to do our selves- ‘65 barracuda. I’m not taking out the rear glass. I have gotten the windshield out- but it has a very small crack :(. I can think of a lot of things I would rather do!
I have done airplanes before- not my favorite thing to do!