These days I have a property manager for the bulk of my units  so I can't promise to recommend the "best" software but I can give you some suggestions that are free/low cost and that are sufficient for most landlords until they reach double digit units(or even more).  

Investing in long-term rental properties with the goal of earning a double-digit return can be done—but it requires patience and diligence.

Did they inspect with video camera certifying it is OK to use?

I have a few Z wave plugs I am going to try so I can turn on and off lights remotely here and there.I also have a Eufy solar camera to put up.

Digital nomads are typically in the 1-3 month range because they like to move around - to them, the experience is just as important/more important than the property itself.

I've been in the building space for many years across the country, and I have never seen a scenario where you can get into a brand new build for $275k that immediately appraises for ~$330k to $360k, has double digit ROI on cash flow alone & is in an A class area with water access. 

If you've already started, the most invasive thing you can do is to install a WiFi camera/security so you can watch the rehab and make sure they are doing what they say.

And the USPS will send you digital images of your mail if you sign up for that service.

When I attend the various REI conventions many of the companies in the Exhibit areas are Tech companies that are putting Direct Mail and Cold calling out of business with digital marketing approaches.For me personally, Whenever I've received Direct Mail envelopes in the mail for any of my properties, I just throw them in the trash without even opening them, partly because I'm usually not selling any of my properties, and if I were to sell I know what I'm doing so a Wholesaler would never be factored into my sales channel. 

Bring with you a notepad & pen, camera, 12 inch ruler, and flashlight.