These do require more time and organization though.Looking forward, after 5+ years of owning a property, assuming you bought in an appreciating area, you should have enough equity built up via tenants paying down your mortgage for you and appreciation to refinance out of the VA loan (if you haven't already) or even cashout to buy more or to supplement your earnings.Theoretically, if you have enough properties you could refinance at least one a year.

Unless there is a history of STRs in the property already and you have experience with STR, you really wouldn't be able to supplement your income with that. 

If you really want to supplement your income, my thought would be to take out a HE loan (or some other 2nd position loan) and use that to fund a down payment on a property.

The boss I was working for when  I read RDPD was a big factor in shifting my thinking from "supplement my retirement" to "get me the heck out of here!" 

I want to get into real estate investing on the side for the long term goal of hopefully retiring early and supplementing income.

In addition we would like the flexibility for me to be able to supplement my income or leave my employer as we see fit.

You can work limited hours in so many different capacities that you want to keep that for longer than you think to keep supplementing more options.

This can provide a steady stream of income to supplement your W2 salary and build wealth over time. 

We had PM teams that ran, on average, at 2x staffing for sec8, and FT maintenance staff supplemented with PT and outside vendors.  

Or is RE just a supplement?