I went to this (Saturday, Sep 22). They said that Sunday's open house is canceled because they expect awful weather.
It was even more rural and rustic than described in this thread. Almost everything was on just straight up grass, not even gravel roads, and you can forget about paved. That said, they had an impressive number of tanks and APCs, and almost every one was manned by historical reenactors in period uniform who were enthusiastic to talk about what unit they were portraying. Plenty of chances to be photographed holding historic guns too if you're into that.
I went with my dad, who is a defector from Communist Poland. His first job out of school in Poland was working in a factory that built tanks and self-propelled anti-aircraft systems, so he was happy to see that there were some Soviet vehicles too. There was actually a group that portrayed Polish WWII soldiers, who had come up all the way from South Carolina. When they met an actual Polish person, they got pretty excited.
My favorites, though, were the people who portrayed American soldiers from the liberation of Grenada. They had an authentic 1980's cassette player to show how soldiers of that era listened to music.