Great example of how to use youth as the only component of your life. 

Built-in Roth components, spousal contributions, and an additional tax exemption also apply to the Solo 401k.

The issue is how do we finance it and write the offer since there is a real estate component and business for sale?

Comps: The closest comp on vickers ave (less than 0.5mi away sold for $262k on 1/23/19 and it's a smaller 2/1 816sqft).

This gets somewhat better if there's a value added component.

They looked at total assets but my impression from questions I've been asked is that liquidity was a key component. 

Fine for more seasoned investors, but tougher for newer ones.That said, I have always thought the brrrrr acronym  was missing 2 important components- Seasoning and Costs. 

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.

They also act as a very significant and very important risk and privacy buffer over and above the work component.

If your company does a match, that is also an instant boost to your starting capitalization.If your plan offers a Roth component, you should seriously look at that.