@Ellie Narie,
Let me just say, as someone who has managed D- areas, and recently sold the ones in the really bad areas-- it's not what you think it will be.
I would NOT recommend doing it, because without being boots on the ground, you can't actually see what's going on. As others have stated, the people who do it successfully are very actively managed, and by active-- let me give you a hint, that means they will probably be late on a normal basis, so you'll need to be posting 5-day pay or quits, and filing for evictions with the courts-- now if it's a good tenant, it will pay before the court date, but that stuff isn't in your spreadsheets, is it? If you aren't local, you'll be hiring an attorney each time, a letter for me costs $250. Another thing you have to realize, in really bad, D- areas.. property damage is normal from random acts, before I sold one of my houses-- the front window got broken TWO times by random kids throwing bricks at it, and when it was vacant-- they broke multiple windows and kicked in the door, just for a place to hang out. I was so happy to sell, just to not deal with the random damages! Without a doubt, had the most turnover and stress there too. You can have the best security cameras, and lighting, but guess what-- the streets know when a house is vacant. Another house in a D area, the local group of guys just decided to kick in my 6 ft security fence, no reason/logic, they were just mad because it added extra time and they couldn't cut through our yard. Another house we had to replace the window because random gun fire, and also had to replace the door because the cops raided it afterwards to make sure no one was harmed. Your spreadsheet doesn't factor in the logistics of a warzone! I guess those weren't on the spreadsheet either that made a D- look like the best option! That's not even touching the amount of deferred maintence you will experience!
If you do move forward, absolutely hire a local property manager... The difference between a C vs. D is huge IMO! I like @Jay Hinrichs term "Financial Suicide" because that's what it really is! I guarantee you'll be here in a few years, maybe you will last 5-- and post about your stories as to why not to buy a D- property. Listen to those who have experience.
GO FOR A "C" PROPERTY! Trust me, it's different!