There is no magic bullet or one size shoe fits all.

You can remotely monitor the property and address any potential issues quickly.Automated tasks: Smart lights can be programmed to turn on/off automatically, saving energy and adding a touch of security by creating the illusion of occupancy when the property is vacant.Consider using a smart home hub like Google Home or Amazon Echo.

I would rather spend my time and energy on something else.I got into this for FIRE; self managing properties doesn't align with my goals from real estate.

Energy Efficiency:Invest in energy-efficient appliances and fixtures.

Because most want a magic bullet without taking action and the results are the same.  

But with 4 kids in their teens/twenties now, seems like that money would be far better used if one of them has entrepenurial ideas (and energy and time). 

That's just asking for trouble.If you want to consider renting it, focus your energy on finding a good property manager, then follow their advice.Remember: cheaper doesn't mean you'll make more money.Start by going to www.narpm.org to search their directory of managers.

Side note: Anybody else get some serious "fan girl/boy" energy when people like @Dave Meyer comment on these posts.

There are a lot of energy and resources that go into getting the snowball rolling, so that's what I invest in right now. 

As far as replacing your current interest rates of 3.5-4.5%, that is a bullet you would have to bite to pursue access to equity.