While it is rough people fix them up in this condition all the time. Also the man didn't ask about the rust so maybe he isn't worried and/or doesn't care to fix it. Maybe, like the previous owner, he wants it for a hunting rig...or a rig ready for the apocalypse
. Though the advice given is valid if you want to save time and money restoring this thing.
Anyways, the top, the crack in the front...I am not sure I see a crack. It looks like a PO put caulking up around the top/windshield frame to seal it. Hard to tell tho.
The other crack? You talking about the seam running down the middle of the inside roof? That's supposed to be there. Are there any cracks on the outside down that seam?