How to estimate a half finished rehab?

[Nick Montville]

I'm looking at a 3 family in MA, the previous owner gutted the whole thing down to studs and redid the entire electrical before giving up on it. Is there any way to ballpark estimate finishing the rehab at a, short of hiring a contractor to do a walk through with me, to decide if it's even worth looking into? I'd probably be shooting for a mid-range price point. It's a 9 bed, 3 bath, about 3000sqft Thanks everyone!