My son currently lives in the townhouse b/c he is going to school and works in the area.Since he is young and starting out in life, I would like for him to only cover the basic costs (taxes, HOA, utilities) just enough for me to break even (I believe that will put him slightly little lower than market rent rates). 

One thing to think about is when doing heloc on primary if you want to refinance you need to get their signoff as well as your primary loan which could cause complications. 

Sounds like you found a profitable niche 

I also like the strategies outlined in Brandon Turner's "Rental Property Investing" book.  

You will need to make sure that are no gaps in windows, doors, etc and that the HVAC system is well maintained as a tenant could argue that lack of remediation is the culprit for a high utility bill.

For instance, properties with an accessory dwelling unit (ADU) on the lot that can be implemented as a long-term or short-term rental can perform exceptionally well.

But ya have to make some educated prognostications in life.Add this to the information your processing - What your talking about doing is eliminating around $4000 or interest expense (which is deductible anyway so really could be a real impact of eliminating $2800 or so) of debt in exchange for paying over $10K in capital gains tax (don't forget possible state gains tax as well).  

Also great deal as well for youHow is it dealing with voucher holders in duplex's?

We stick to high quality neighborhoods and homes and are doing really well with it.

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