HM opened in August of 1969, and Walt died in late 1966. He had a hand in it, but the finished product was somewhat different from what he had described earlier as "a museum of the weird".
My favorite was the Mine Train (of course). A train-based attraction, it was said this was one of his favorites. And it had that huge desert to circle through! At the time, Nature's Wonderland had more animatronics than any other single attraction had. It was quite a trip.
"Say, uh, ever hear of the devil's paint pots? Real mystery of the desert. Bubblin' pots of mud in all kinds of colors."