1) Automatically time your slides so that the show begins, and ends, precisely when its audio track does. You can vary the timing of the various slides later in PRE, by performing the following action: Break Apart the Slide Show (separates the slides from one another and from the audio track that you applied in PSE).
2) Automatically apply,instantly, pan and zoom to all the slides in the show. Later, when editing in PRE, you can remove the P&Z and keyframe as desired--highly preferable to keyframing each and every slide in PRE (unless you are using the Copy and Paste Attribute functions, which are also very quick).
All fine tuning of the show--applying effects, transitions, plus your usual introductory and ending materials, etc-- should be done in PRE, after "sending" the show to PRE from PSE.