I hate to be that person, but I got the hardcore ending on my first try, without trying too hard. The most difficult part was keeping the people happy, but utilizing the "cultural exchange" in Diplomacy was enough for it to not be an issue at the end. I barely touched the taxes.
I realized that the budget wasn't going to be an issue as I continued, so I stopped worrying about things that increased my expenses past the second year or so. Also, I worked on getting the power plant and total brainwashing as soon as I could, along with constantly being at war with the Island States.
I also did not build the labor camps until almost the very last step. I had a good system going using the Diplomacy tab, so I didn't want to ruin it.
Maybe I just got lucky, so take my advice with a grain of salt :).