Apparently it didn't go perfectly and for a while Disney executives called it "Black Sunday" and referred to July 17, 1955 as the dedication with July 18, 1955 as opening day.To all who come to this happy place: Welcome. Disneyland is your land. Here age relives fond memories of the past, and here youth may savor the challenge and promise of the future. Disneyland is dedicated to the ideals, the dreams, and the hard facts that have created America, with the hope that it will be a source of joy and inspiration to all the world.—Walter E. Disney, July 17, 1955
Page 39 of the August 15, 1955 Life Magazine has an multi-page article with photos and you can read it here.
You might enjoy these ads featuring Disneyland.
Swift's Premium Franks were served at Disneyland
April 16, 1956 Life Magazine
1956 Nash photographed in Disneyland
January 30, 1956 Life Magazine
Seats that lay flat so the weary wee ones can nap! (You can see a lot more if you click on these images and look for the magnifying glass)
March 19, 1956 Life Magazine
April 30, 1956 Life Magazine
Insurance By North America
May 27, 1957 Life Magazine
June 17, 1957 Life Magazine
April 28, 1958 Life Magazine
May 26, 1958 Life Magazine
Happy Birthday Disneyland!