Mainly from google, but also from books from individuals such as David Greene and  Dave Van Horn. 

The main difference is in the risk. 

Corner lot, 11x17 deck, 2 car driveway, walk-in closet in master bedroom, door to main bathroom from master bedroom, a basement great for my work shop, right next to a park and many amenities.

They deposit it and the day it clears I transfer it over to my main one.

I have family and friends in the general area so traveling there to look at properties/meet with a team can also be excuses to visit family.Those are the main reasons.

The main culprit, which are the renters living adjacent to my bedroom windows: are what I presume to be family of 8 to 10 people: an old man, an older woman, another woman in her 30's and another woman, a man, 3 toddlers and 2 high school aged kids - all living in a 3 bedroom/2 bath home.

Ideally, you will be able to find recently (last 6 months, or even the last few weeks) sold properties (at least three) that are as identical in features (style, beds, baths, square footage, lot size, condition) in the same neighborhood as your subject property. 

As far as home features go....

Just to add for the ramp as an example, if the main door is 2' up from the parking lot, you would need a 24' ramp.

There are quite many Accounting apps to choose from.For me, online database (keep track of expenses from anywhere with phone/laptop/assistants) and receipt scanning through phone are the 2 most important features.