You NEED to go there. I was sitting out front waiting for it to open the last time I was there a couple of years ago and still missed stuff. A guy on the model car board I go to was just there on my recommendation and is posting some photos and already shown 2 that I don't even remember. Here's a link to my Smugmug file if you want to check out some of the stuff:
2010-08-26 Hays Truck & Heidrich Ag Museum - whulsey's Photos