I bought an SFR cash because the comparable sales within a mile were around 70k and the "as is" close now price was 20k. 

Population characteristics (www.usa/com/rank) Population:Population growth:Population density:Population compared to other cities in state:Fast growing area?

They are both quick ways to compare opportunities within the same market, but trying to track a relationship seems... not useful at all. 

The higher yield is the reward for taking on the higher risk asset.This is also an important concept.

One duplex through the other day that looks promising (still a low 5% cap but that seems to be amazing compared to all the other properties ive been sifting through). 

He's helped a lot of my house hack clients navigate comparing conventional, FHA, Home Possible as resources for only putting 3.5-5% down on an owner occupy multifamily.  

Compared to an IRA, Solo 401k contribution limits are roughly ten times higher.There is no custodial requirement for the 401k.You don't need the additional expense and administration of an LLC to have checkbook control.There is a built in-Roth component whereas IRAs are either traditional or Roth, not both.A spouse can also participate in the same Solo 401k plan.The Solo 401k has additional tax benefits over an IRA when investing into real estate using leverage.You can borrow from a 401k, but not an IRABoth C-Corps and LLCs can adopt a Solo 401k.

I have not discussed comparable building specs with a traditional builder, yet. 

Also what does everyone think of using epoxy paint in the floors compared to laminate?

How hard is to get tenants for house that is relatively far from public transportation compare to one that is very close?