There are two excellent books I have come across:
ISBN 080694840X & 0806965444 which are now out of print but my library had copies of both. I was after the second one for my sash window construction and is by far the best source of detail on making your own sash windows. Worth the read and I will be using my Freud router bits to make the sash but I needed details on the casement for the sash itself which this provides.
On doors though it has some excellent info as well. I went to my local Habitat Re-Fit store and picked up an interior door from the 1800's I was planning to reproduce for my interior doors as well and this book had similar doors in them! With construction details but they are pretty straighforward to copy anyways.
On exterior doors they had alot to choose from style wise and gave general principles on exterior door construction. I will basically take a sheet of 3/4" plywood. Edge trim it with 1/4" pine. Then glue/nail on 1x8 or 1x6 T&G pine flooring on both sides vertically. Will give a 2 1/4" door that is solid and dimensionally stable in all directions. Also gave details on adding lights to windows etc.
Worth looking at those books forsure. Out of print as there are not many of us interested in our door or window making!
Found a local source of 8/4 white oak for my door sills. Beautiful but not cheap!