I was for a time in the 90's very into urban exploration. I heard about it on a radio show, maybe TAL. I ended up getting this little zerox zine called "infiltration" it had a great story of a group that explored some abandoned missile silos.
When I was in graduate school in St. Louis, I frequently explored an old hospital, it made for great photos. Fun stuff, but you have to be careful and watchful.
A few other movies:
I am Legend
You might look for some on YouTube, but be careful, could set your kids off into territory that might encourage them to get arrested. Doesn't seem like most spend much time getting permission or preparing for possible problems.
On the TV front, and more wholesome, you might take a look at back episodes of the GPAA "Gold Fever" show with Tom Massee. He's always digging around in old mines or in ghost towns.