Estimating ARV

[Joe Ebanks]

I found a house that is in terrible shape. I think I can get it for very cheap. The property alone is probably worth what I will pay for the house. It needs just about everything to be done that a house could possibly need. I'm specifically worried about:

I found mold in the basement. I believe it is sandstone. I'm not positive. There was green mold all over this stuff. Also found crackings in the stone. It was painted over with something to hold the water in (maybe making it worse?) as I peeled that off the stone crumbled. Also on the outside I noticed they covered this stuff up. So its hard to see just how bad it is. I'm unsure what the solution is and how much that would cost. 

2nd big problem on the first floor the roof has a hole in it. They added a dropdown roof (purely to hide the damage i think) which is in bad shape. No idea what needs to be done. All the house was carpeted and the floors were wooden. I dont think the floor/ceiling needs major work but really i dont know. 

The HVAC was very old, water heater very old. Windows very old. Probably terribly inefficient. 

The roof did not have any leaks but from the attic I could see the insulation was all quite old (surprise). 

Overall its a small house, on a small property. But I can get it for really cheap, and after fixing it up I think I could get 3 solid bedrooms to produce at least 1k/month total. Its in a nice college town.

This will be my first fix up so I really dont know what to even do and certainly dont know how much that will cost! I'd like to learn to fix these things myself and am planning on getting onto youtube to find out. If anyone can help me estimate the capex here that would be great! 

I'm not sure if I can get away with not fixing all the windows, not replacing the hold HVAC, and stuff like that. What do you guys think?