Secondly, calendar and email functions/apps on computers and smartphones provide great records and a log.

What about tenants that don't have smart phones or  aren't comfortable using mobile apps? 

We think a smartphone app-type, GPS-enabled time tracking tool for tasks and hours would be a good start.

I mean smart phones are obsolete as soon as you buy it.

Just read over previous message, Thanks for overlooking the typos that my smartphone autocorrected.

(although, with the new smart phone technology, they do require gmail accounts, as such, sending from that account from your phone is fine, but you should be sending to people who already know you have a real email account.

Parents buy their 11 year olds smartphones.  

Computer or Smartphone, an internet connection, a blank Purchase and Sales Agreement, and Assignment Contract, an investor friendly title company or lawyer(depending on which one your state uses for closings), a bank account..

As to your numerical goal, you can certainly exceed that (and ultimately by a large margin).Most would-be real estate investors get distracted along the way but have lots of smart phone apps.

You can invite as many people as you wish to access the software both on their laptops and on their smartphones.