Once you are confident you have all the data fairly accurate, then look at the Cash on Cash Return for the first year.  

It's all about the guarantor on the lease, experience in that chosen industry, a track record of success, liquidity and net worth of the guarantor, and how easily attachable the assets are if something goes wrong.For instance I would never front money for tenant improvements on a business that is not a proven performer.

Past performance is no guarantee of future performance, nor a good indicator of what the property is worth.

The option can {many would say, should} contain the future Agreement of Purchase and Sale (APS), with all the terms and conditions of the future sale, laid out, as a Schedule to the Option agreement/contract.In exchange for the right to purchase the property at the {strike} price established by the option contract, an option fee is paid by the purchaser of the option to the writer/provider of the option.I would keep the two agreements separate (as if they are with two different people) and have no performance ties between them (i.e. no rent credits, no financing of the down payment, etc).  

Thanks @Chris Allenwhich list do you find to be the most accurate? 

Most everyone can gut a home, but knowing how to estimate costs,  see what needs fixed and be able to accurately estimate  a job, project is critical to you even having a chance at succeeding.

The next step in my process is to check the rental rates on rentometer.com to see if the rent listed on the MLS is accurate. 

Last year I started my own investment company with the goal of buying residential and commercial real estate through non-performing notes to build a portfolio of short and long term investments. 

Also, because I don't know much about repairs and costs, I am afraid I wouldn't really be able to accurately estimate what the costs would be and would go broke from misestimating the costs.

PLLC is an option for anyone who has a license to perform a service (lawyers, real estate agents, ect.)