how low can it really realistically go? and how fast?
Properties could fall to essentially zero, become abandoned by the lender and then demolished by the city. This is already happening in some parts of the country.
Even if it stabilizes at something like 100k, think of who your neighbors might be before locking yourself into a 30-year mortgage.
The problem with the IE is a combination of rampant over-building combined with a local economy itself heavily dependent on real-estate is going create a massive inventory overhang. There are simply more properties than people willing to buy them out there.