My first trip was Memorial Day weekend of 1978. I was 13. It was the first time any of us had ever flown which was exciting by itself. We flew Eastern Airlines (the official airline of WDW) from Philly to Orlando. The current airport didn't exist yet. When we reached Orlando, we walked down the stairs onto to the tarmac to reach the terminal.
We stayed at the Golf Resort Hotel (later the Disney Inn and now Shades of Green). There were only 3 hotels and 1 park. They still had the ticket books. A book with 18 assorted tickets was $19.50 for adults and $16.50 for kids.
At a couple of places in the park, there were vending machines that for a nickel dispensed a postcard. There were sets from Country Bears and Pirates with reproductions of the original concept art for the attractions.
The afternoon parade was celebrating Mickey's 50th birthday. There were not many Disney characters in the parade, as there were not nearly as many Disney characters back then. Much of the parade was generic characters like cowboys, Victorian couples, etc.
When I look back at photos and movies we took during the trip, I'm amazed at how few people were there, even during the afternoon parade. WDW wasn't the International destination it is today. Even during peak season, the crowds were nothing compared to now.
Of course, like all of you, I was hooked. I had been a huge Disney fan long before this trip and finally getting to go was just icing on the cake. I made a few more trips during high school, then after med school graduated to the annual (or more) trips that we are lucky enough to enjoy now.
Steve