Tax assessments are notorious for being off the mark.Is there any deal to be had here if I could get her down on the price?

Hope the abode is treating you and your family well.Short sales purchases are actually notorious for being an absolute time-suck.  

Short sales are notorious for taking forever to close.

They are notoriously inflexible about treating a purchasing business entity separately from the owner/manager of the business.

When they leave, we are going to move a wall and paint the rest of the unit for tenants in September.The last unit comes free at the end of June and new tenant moves in 4-days later :)... and we even rented the notorious 3-bdrm duplex for July.

I've been investigating doing real estate investing out of state, since where I live (Massachusetts) is not only an overpriced real estate market but notoriously landlord unfriendly and hostile toward small business in general.

Finding a good wholesaler is another option, but 1) they are notoriously hard to find, and 2) with all the cash flying around the market these days, wholesalers are able to ask for more, making the margins smaller.

You may have what is referred to as an "easement by prescription" created by the open, notorious, uninterrupted, hostile, and adverse use of another's land for a period set by statute.

They are notoriously way off. 

PermittingLocal building departments have different rules and procedures for permitting and some take a notoriously long-time to get permits approved which could add several weeks to your schedule.