If you are talking of the BP calculator I usually do it on a per building basis so I add up the rents just because the mortgage Is for the whole building and expenses like water, insurance, taxes lawn care, snow removal will also be for the full building makes it easier to compare apples to apples

My 2 cents, Elk Grove is more of a bedroom community for commuters although Apple does have a campus. 

Obviously you could add the fees in for AirBnB but I'm trying to work out the best way to compare different data sources that aren't actually apples to apples.

Create an online storage account with Google Drive, Dropbox or Apple drive to save files such as Reciepts.Open up a separate bank account / credit card that you just run your rental expenses.Open an excel file or accounting program to properly classify your rental expenses.Best of luck

  $400,000 resale homes, 5 minutes from new Apple campus. 

I was a C programmer.I worked at NeXT (think today's Apple).

You won't really be comparing apples to apples.

Do one task at a time in each app so you can compare apples to apples.Load a property with pictures and details.Market that property.See what your marketing looks like from the public's perspective.Submit a fake application to see how easy the process is.

Unfortunately there are bad apples in every industry. 

You should end up with something like this, allowing you for an apple-to-apple comparisson: