I think the key is the delivery - I'm not a huge fan of "We're investors so we dont offer retail" as that translates to "We're investors so we're looking to make our money off of you".Instead, I'd phrase it like, "I wish I could offer you top-dollar but as an investor I'm looking to renovate and sell this house so I need some room to make my profit. 

He translates for them. 

This targeting translates to people over the age of 50 who are close to paying down their mortgage and holding equity in their property.

An important question would be, how much interest will you get paid, and how much return does that translate to over a given time period?

If you are worried that rents are low but do not want to do lose the tenant you might could try and alter the lease if option period is open to include additional percentage rent above a certain sales level.

I would think this can translate to anywhere with a competitive market though.

Keep in mind, although it may not be completely translated in equity there is serious value in owning a property with all of the deferred maintenance addressed. 

There's  maybe a potential as you said to quit your 9 to 5, which will translate in more time and potentially tax savings as you might be able to claim "active real estate professional" status.

That translates into an offer in the range of $125,000.

Unfortunately I am in another state, but I think the skills translate.