Is this type of investing reliable enough to be part of your retirement plan?

I am 42 years old and consider my stock market investments to be my retirement money.

I assume any new mortgage can be covered by the rental income of both units, given the high and stable rents in our area.Any advice would be greatly appreciated!

I am a retired Air Force officer and first entered real estate investing about 20 years ago as a reluctant landlord. 

By nighttime, I divide my time into reading books, spending time with my family, and planning to retire by 40.

You might get people with better jobs and seems more stable, but you also might come across people who expect more because they pay more.So with the A-class you are looking at, you will have to deal with all that.

But the market is a lot more stable now, with a lot of sustainable growth.

Lewiston also seems to be more stable since it doesn't rely on a student population.  2) REI groups. 

It's more of a retirement goal but gives us some flexibility and we have other assets focused on driving more income properties. :)

I'm retired now, checked out annuities and none can pay me the $1,500/month unless I invest a good chunk of cash.