While the self-directed IRA is a great structure for investing into real estate and other alternative assets, the Solo 401k is widely considered to be even better.Compared to an IRA, Solo 401k contribution limits are roughly ten times higher and there is no custodial requirement for the 401k.

Knowing this on the front end limits any exposure to major fluctuations on deal terms once submitted.

What if I were to tell you the Investor A triplex was sold two years later for a $100K profit whereas Investor B is run down and exhausted from managing their four "C" neighborhood single family homes and when investor B goes to sell,  they can only attract break even offers because the only buyers who would step to the plate were investors who were not willing to pay retail with so much distressed opportunity available in the "C" neighborhood due to limited barriers of entry. 

Between forced appreciation on general improvements on the property and the capacity to add an additional residential structure, the sky was the limit on value growth.

That said, it could be that the location of your property has some sort of local ordinance that has a 90-day limit, and Airbnb is simply following that.

There are some guidelines in place that limit the total exposure to 80% LTV which is good.

Your best option to is use your father-in-law as the builder in a very limited scope. 

The qualifying attributes are consistently: quick close, no tax return, limited documentation….

Could you possibly have the property right outside city limits?

They do this by adding you on to one of their 'perfect' credit cards that have a high limit, usage, and also paid off every month.