I've been using Trulia for their crime map, Rentometer and Craigslist to estimate rent in the area, colleges and universities to help determine popularity.. what else should I be looking at?

You also need to call an eviction office as each court workload is different.Vacancy assume 8% (1 month) for estimating reason.I will carry more liability insurance as extra.

I have seen estimates for new construction of $125-$200/sf, but that includes the actual structure, which I already have.

What is your estimated ROI?

I currently estimate its worth $185,000.

As they only count income minus debt payment (including property taxes/insurance) but often don’t include property management, or estimated repairs. 

I'm running the numbers on some different properties and I just want to make sure I'm estimating my costs right.

"And this is not even to mention the fact that if I hire a GC, a lot of what he will do is just sub out much of the work, in which case I'm basically paying him a "finders fee" for a sub that for all I know I could have found a better/cheaper one myself"......If you think that GC's make all of their profit by "accumulating" a list of sub-contractors and sitting at the coffee shop doing nothing you're so far over your head you're looking up at the Marianis Trench......

Soliciting any and all advice before signing the GC estimate.

Have you gotten another estimate from a contractor that is not a 'friend of the family'?