Interior is basically done and I still need to paint and do some minor exterior work.

Also, I think it will depend on the quality and style of the interior finish as well.

Seeing my wealth increase hundreds of thousands of dollars due to appreciation in interior locations has shown me that.Everything outside of California and the east coast is not a ghetto Detroit neighborhood with D class tenants and negative appreciation.

The below estimates are based purely on research and have not been quoted – again, I’m looking to see if I’m in the right ballpark.Cost estimates:Electrical/Wiring: $10K ($3/sqft – labor + material)Drywall: $6.5K ($2/sqft – labor + material)Plumbing: $10K ($3/sqft – labor + material)Flooring: $8.7K ($2.79/sqft – just material)Interior Paint: $2K (mostly material, potentially contracting out ceilings and high places)Kitchen: $15K (based on salvaging some of the cabinets, new countertops and appliances)Bathrooms: $15K ($5K/bathroom, installing mostly myself except showers/tubs)Holding cost: $7.5K ($2.5K/month interest only payments for 3 months, discussed below)Titling fees: $5K (for seller financing, discussed below)Total Cost: ~$80KHow accurate is this?

I know I was a licensed assessor for a number of years..You really need to get inside to confirm the interior condition and mechanical age before you can offer. 40% seems really low for expenses on a building that age especially with that water bill. 

As for rental boxes, I have begun installing mail slots on an interior door.

(As that can depend on the markets you're operating in)Also can an Agent help with Design of Home to make appealing to prospective buyer or Should I seek an Architect or Interior Designer?

I've spoken to my mother(who's an interior designer w/ 30+ years of experience buying/remodelling), multiple contractors, investors and lots of people with experience - they all tell me my margin of error is very high - I would have to be seriously unlucky or very dumb to screw this up.That said, I'm still scared "witless" and am extremely nervous to sign a contract - I'm supposed to receive a contractor bid (from a 203k experienced contractor) and nervous that I'm putting myself in a tough position.

Get a mobile crane, throw up SIP Panels in a week - boom you gotta exterior and interior framed building.

I would definitely paint the interior to freshen it up and consider new carpet and kitchen flooring.