Because of the nature of a tax lien, it would be difficult to obtain financing from a commercial lender secured by the tax lien itself.  

With current interest rates (at least in Canada and guessing the US is similar), you'd be further ahead investing that money elsewhere and continuing to let the tenant pay down the mortgage with their rent. 

With homes staying on the market longer, be aware of interest rates, as they can influence buyer affordability.

With a Condo, couple things to note:1) Financing can be a challenge, but as long as the building is in good condition, you should be fine.

Patience is a virtue that may be worth practicing.  

The monthly payment difference would be something like $100.

What should I be looking at when trying to consider an appropriate offer (especially if I can't see the property since I'm investing out of state)?

Obviously geographically the risk of a major earthquake is real with the New Madrid fault being close by.

Correctly it should be called the STE calculator.  

This exemption can be a game-changer when it comes to reducing your property tax liability.