Hi Nina.
I've only dipped into Neptune so far. Found it fascinating though, and have used the cookbook part to get my thinking going about certain aspects and house placements many times.
I think Barriers and Boundaries is a great one for anyone approaching the Saturn Return, because she deals with Saturn in depth. Saturn - A New Look At An Old Devil is also very good for looking at the particular placements and aspects of Saturn, to help you connect the stuff in Barriers And Boundaries to your own chart. I found Saturn incredibly helpful because Greene gives great insights into each factor before she looks at how it connects with Saturn in the birth chart. I thought Arroyo's Astrology Karma And Transformation was pretty good for Saturn returns and for transits generally.
Feel free to ask if you want a 2nd opinion on how you've interpreted the return, either by starting a thread and sending me a PM to draw my attention to it, or just by PM
Best wishes
Mike