This hike is in the SE corner of Capitol Forest (in the Mima Falls area, and about 2 miles before you get to the Bob Brammert hiking trail)
To get to it, go down Bourdeaux Rd, you will see an old mossy building on the left and a small turnout for two cars on the left. (And this is before you get to the entrance to Capitol Forest.) Park there and follow the trail into the woods (there's two small openings going into the woods, choose the one closest to Capitol Forest and you will be able to get to a bridge that takes you to the ruins) It's approx 1/4-1/2 mile walk it's very close to the road, but hidden enough you won't see it when driving.
Also, it's been very muddy the 2 times I have been there, so wear boots. Also, you may want to wear pants, I wore shorts one time I was scratched up when I was done.
The very first time I went the place was so spooky and creepy. The second time, nearly a year later, there was bottles and graffiti everywhere and I was so disappointed. That's ruining this magical place and those who come to see it, so please please do not deface the ruins while you are there.