GRM on a comp comes out low, well that is one data point. 

Whenever you are buying a property out of state you should do a few things to ensure it's as smooth as possible.Don't buy in the roughest neighborhood in the urban core.

This individual is wisely giving himself enough runway to ensure he has the time to complete his project and pay you off according to the terms of your note.

My goal is to find sales within 1/4 mile and 6 months, but I frequently don't have enough data without pushing out both radius and time. 

You can do a basic title search on a sheriff sale property like on any other property:  using a title company, attorney, or a visit to the country records office.This county's data may be online and searchable (sometimes for a fee), so you could try that, too.Best of luck!

If they see a wave of listings in a particular area and learn that there is going to be some major drainage work done two years from now that will significantly impact taxes, unless your going to meetings at city hall or live in the neighborhood, those are likely things you may miss.When you do begin to narrow down properties you like, they may be able to provide you with data that will reaffirm your own in regards to comps in the area, ARV, and the direction of price trends. 

-DonOpendoor Data Scientist

Be conservative with your rehab estimates and ensure you use accurate rents for your area.

It's so hard to time refinancing since you can't ensure that rates will continue to go down. 

ALSO, I would ensure that your agent advertises the home as MultiFamily so it pops up on more investors radar.