Go to Etsy and search for "rental property tracker," and you will find hundreds of nice spreadsheets to track 10-20 rentals, usually for under $10.Software has extremely helpful features like online payments, marketing syndication (click a button, and your property is advertised on multiple sites), electronic document review/signing, maintenance tracking, and owner reports.

I would give Schlage a call and see if they can access it remotely from the server.

Right on @Don Konipol: And another big one is that advertising a property for sale that you don't own, is called "being a real estate agent".

They could still stay in the house and have access to the entire property. 

I feel the community and benefits would be SO much more accessible with an app!

Is it a good idea to incorporate logos, portraits, and QR codes for direct access to my site? 

As far as screening tenants for a long term rental, what about having a Property Management company do the advertising and screening of tenants?

I looked at land and on same street there are rentals renting for 200 less than people being advertised higher I'm like wow people are going to be taken advantage of. that was in October I'm sure it's even worse now 

Two were in a very rural area with limited access, and one was in a flood zone.

The duplex was vacant when we bought it so I’ll be advertising for a tenant soon.