and the roof didn't cave in on you
Oh.., no chance of that. This wasn't one of those, 'almost caving in' types. The access point would be fine, if only I was a little younger. It's take me twice as long as @anidiotexplores to get through holes likes these.
That opening is about the size of a cave I used to explore when I was younger! I wouldn't even try to crawl in there now, I'm not as young as I once was... Age does slow us all down a little, sometimes a lot!