I had six doors in this renovation, not counting the cabinet doors. However, five of them were either new doors or doors which I'd stripped a couple of years ago. I did the heat gun route first. That removed like 80% of the paint. Then I moved over to chemical stripper (Klean Strip). I wrote an article about my approach to woodwork stripping over on Old House Web which has more detail about it.

The doors are red oak. Actually, I've replaced virtually all of the woodwork in this house. All the wood you see in the bedroom reno for instance is brand new stuff, except for the entry and single closet door.