They would only net a few grand after selling costs if they sold this.  

The numbers are certainly not accurate (just a made up example), but it seems like the choice is to sell today and get (let's say) ~$50K one-time; or keep it and get an accumulated $500K over 25 years or so, plus have a legacy to leave when I die and a bank I can potentially withdraw from every 5 years or so with another refi as/if needed in the future.I cannot speak for you, but for me, I see selling for cash today as a crime against my future self, child and future grand-children.

Not a huge deal in the grand scheme but something you want to know as you analyze the deal. 

@Kristina Krich if you want a market with a population growing at 6% annually I would recommend new builds in Casa Grande, AZ.

Furnance $3100, water heater $1000, flooring, couple grand, bathroom tub couple grand. 

Buying a primary residence requires the lowest down payment and will get you the lowest available interest rate.If you don’t want to move again then your next best option might be to buy a new or almost new single family home in a fringe area like casa grande for $300k.

The Rio Grande Valley includes the following areas: McAllen, Edinburg, Pharr, San Juan, Alamo, Brownsville, Donna, Harlingen, La Feria, Mercedes, Mission, Port Isabel, South Padre Island, and Weslaco. https://riograndeguardian.com/edinburg-is-now-the-12th-faste...

I own 2 here in the Bay Area and will be closing on my 6th (For a grand total of 8 units) unit in Cleveland next Friday. 

I.E Midlothian, Cedar Hill, Grand Prairie etc.?

If you try to hit a home run or grand slam, don't be surprised if you strike out.