Property is 4/2, 2000sq ft.

Trust that RTR is referring you to good companies, but just verify.

What is the 20% processing fee?

With a purchase price of $250k, your rent is WAY too low!

It also depends on how you hold your properties; LLC, S Corp etc... as to what the agent will recommend.

If your property is the only one without a driveway, then yes, it may lower your ARV.One of the properties I own has a neighboring property that is the only property in the area without a backyard and without a driveway, and it is fairly lower than all the neighboring properties, although it is nearly identical in structure.

Is there a quick way to estimate what those other costs will be monthly to make sure my calculations are accurate?

PS; I house-hacked with my brother for 2 years. 

Let me know if there is anything I can do to help you.

You can probably pay for a course when one of the sucker roadshows comes thru town, but it is a ton of money.