For books, I used to recommend poeple start with Spirit of Aikido by K Ueshiba.(despite the techniques in the middle of the book).
Check out almost any of John Stevens' books.
Kodo - Ancient Ways is about training.
Dave Lowry does a good job on traditional Martial Arts training.
That should get you started.
As far as shadow training - or walking through a techniques without a partner. If you are doing this to try to get repitions in of proper movement, you should also consider walking through the ukemi for each technique.
Starting to read Spirit of Aikido by K Ueshiba .... may the
be with you