I am ready to reinstall the interior in a 65 coupe.
I am pretty sure the headliner goes in first and that is done.

Questions...
1. Should the dash pad go in before or after the windshield?
2. Should the package tray (rear) go in before or after the rear window?

If you have experience with interior assembly, what worked best for you? What do you recommend?

 

windows first.

if you have never installed windows it is probable that they will leak. its very difficult to seal them properly.

 

mustang monthly has a good article on windshield install. The key is sealant inside the gasket, and on the window channel. It'll make sense when you read the article. Original glass is thicker than replacement glass, which is important in the sealing the window inside the gasket. Inspect your window channel carefully, I personally found a nice big hole where two panels weren't overlapped at the bottom of the A pillar, had to weld closed. A second set of hands will help. Harbor freight has the suction cup handles cheap BTW.

The trim for the dash pad at the base of the windshield is easier to put in when the windshield is out, but not essential. This means you'll need to put the dash pad in and trim. Sometimes its hard to squeeze a screwdriver in there once the glass is in place.