There still are profitable markets in Southern Utah that I'd explore.

I don't know if an additional day or two might help you.  

@Will Grabert that would be an interesting strategy to explore - thank you - I will look that up!

Took a long time but we were successful.Have you explored owner financing? 

In addition to that I’m using Baselane for rent collection.

Additionally, highlighting the potential for a higher overall return on investment might appeal to his financial goals for his heirs.

I am also on the property management side so if you have any additional questions, please feel free to send me a message!

Land acquisition, permits, foundation, utilities, architect, and on and on but without the additional benefit of profit on the larger sq/ft you'd be selling.

Additionally, if leveraging, ensure you have ability to withstand potentially significant drops in rental rates. 

It sounds like you have some exciting decisions ahead of you regarding your real estate investments.Selling your primary home and reallocating the equity towards a new property and additional rental investments could diversify your portfolio and potentially yield higher returns.Best of luck,Julio