During the 1970's, the Insurance Company Of America sponsored a small guidebook that was given out to visitors to Disneyland. A friend of mine at work kept the one she picked up when she took her family to the park in 1975. It provides a fascinating glimpse of the park at the time.
At this time all attractions required tickets. This guidebook explained the different levels of tickets and what attractions they were good for.
The book also provided maps to the park and all the different lands. There are a lot of attractions listed here that are no longer at the park, including the much beloved Adventure Thru Inner Space in Tomorrowland.
With the Bicentennial celebrations coming the next year, Disneyland had already started advertising their America On Parade spectacular.
This guidebook provides a great look at Disneyland during its 20th year. While it's still a fun place to visit, I'm sure it was just as fun, if not more so, to visit back in the spring of 1975.