To supplement my 401k, IRA, and brokerage accounts, I want to use real estate as an additional vehicle to invest in.To start, I'm currently looking in Northern Indiana (e.g.

new unvented gas heaters advertise that they are for part-time, supplemental heat only for that reason.

I am a software engineering manager by trade but looking to get into real estate as supplemental income. 

My business policy is to not devalue my investments by supplementing tenants rent through charging under market.

I got this from an attorney that I trust.Also the IRS has this to say about it:Here are some tips from the IRS about vacation rentals.You usually report rental income and deductible rental expenses on Schedule E, Supplemental Income and Loss.https://www.irs.gov/newsroom/renting-your-vacation...

The tenants rent payment will supplement their mortgage.

It also has a very nice 1 bed basement apartment that we could use to help supplement the mortgage, & we could potentially rent out both spaces when we leave.My dad is a lawyer (he does not specialize in real estate though) and it would not be too difficult to structure things however we needed to.

During this time there has been partially functioning heat which the tenant supplemented with space heaters.

I will be moving to a more expensive market and my VA loan won't be of much use to me there.My long term goal is to establish enough passive income in retirement (supplementing my military retirement) to give me flexibility at that point in my life. 

Are there any supplements that would help me prepare and better understand the material in lamest terms?