In order to see much of the western side (of Saguaro National Park) you need to travel on a stretch of unpaved road. There are not many places to pull over, so most of my viewing was from the car.
The visitor center didn't open until 9am, and by then, I had gone all through the marked roads. Since it gets hot here, earlier in the day will be cooler.
Given a choice between Saguaro West and Saguaro East- if you only have time for one, go to Saguaro East instead. It is more accessable, had more pull off areas, and view from varying altitudes.
If you own or manage Saguaro West, register now for free tools to enhance your listing, attract new reviews, and respond to reviewers.