This method typically provides an accurate, data-driven view before deciding to move forward with a property.

If you're a relatively new multifamily operator, you'll likely be required to hire a professional management company (inexperienced owners are typically not allowed to self manage the assets).

We need to find a good app/website for them to send rent as well, preferably one that has many things built into it, making it more simple to manage things in one place.

Buy and holds is the key to true wealth with all the benefits of depreciation, appreciation, loan pay down by your tenants, leveraging the equity, cash-flow etc etc, but it often times isn't the active income that pays the bills until you build up a portfolio and even then there's the tenant management or managing your property managers.That's why I'm involved in all 3.

Many property owners rented, and decided not to rebuild, but to sell their homes and use the money to invest, travel, etc., staying in rentals.

We manage several hundred rental properties throughout the San Diego market and I found your post very interesting. 

It isn't having paid off properties that offers security, there are still taxes, insurance, maintenance and management involved. 

These properties are often easier and more affordable to manage.

Can it integrate with your bookkeeping software (like QuickBooks or a property management tool)?

When it comes to managing your mortgage, most homeowners are familiar with refinancing as a way to lower monthly payments or take advantage of better interest rates.