If I knew the size of the units and county that the property is in I could give you a better answer.

If there is a flat section of the roof of any significant size, there absolutely could be 8 layers of roofing material.

it was built in 1990 and it a medium size ranch style. 

Also, it depends on the size of the loan.

Not sure how much you need monthly to quit the rat race, but a building that size for a relatively newbie investor will probably make you broke or hate life without the experience to back it up.

You could expect to see 25-35% returns on your money in a couple of months depending on the size and area for the project.

If they fail to buy, I received significant option money and above market rents all the while off loading maintenance responsibilities to them.My fallback position is they do not exercise the option or they violate the terms of the option so I keep the option fee (typically $10,000 for the size of houses I've been working with). 

They look similar to the one you have in the picture there, but come in a variety of sizes.

This would serve best as a mew construction.The lot size is almost 2 acres.

Is it illegal to ask potential tenants if they can pass a drug test?