The Soil Connect app might be helpful.

Rental: the one I kept as a rental had a PP of $55K and cost $140K to rehab.

I don't think you can get previous landlords with a zillow app. 

I have found  mobile app called Clarem (www.getclarem.com) useful to build a plan and stick to it. 

Be sure your marketing and your application include whether you have a pets/no pets policy; assistance animal policy; ALL adults must complete application and will be named on the Rental Agreement; utility responsibilities; SD requirement; when and how various funds are due (app fee, SD, initial rent, etc).

There are apps but a spiral paper notebook is fine.

My apprehension is that after the initial furnishing, app process, move in, there isn't much to do.

All I would need to do is clear out the basement and post it on the app.

@Zach Edelman dealcheck app.

This has been a side thing for us, and our accounting has been old school manual spreadsheets, along with rent collection varying from tenant to tenant (Zelle, PayPal, cash app, etc…) neither of us are great at keeping up with accounting which makes tax time a nightmare.