I hate to jump on the bandwagon here but there is something about this that just doesn't pass the sniff test. 

Does anybody know of any good online resources to see historical Real Estate Appreciation Data?

Obviously no guarantees, but there is plenty of data supporting it and firsthand accounts of investors achieving that.For your situation, I would focus on 2 things: 1) Act quick, but don't hurry; 2) See how far you're willing to go.  1) If a house meets your criteria, it all adds up, be responsive. 

Extra points for community redevelopment.Ultimately though, don't sweat too much about the data.

I did start a spread sheet to track where I've sent letters, how much I've offered and pulled some data from Zillow and Redfine so when I do get a deal I can see how valid their estimates are.

They have a data base where you can purchase liens/deeds through their relationships with banks and hedge funds. 

Some wouldn't go in an attic, wouldn't go on a roof, wouldn't test every drain or open every window.

@Brian Walters I use Propstream to get my data! 

There’s an additional cost there, but if I was you, I’d consider fronting that cost in advance so you have strong data to evaluate your potential investment properties with.3.)

What data points are your lenders expecting?