Investment options in such a plan would not be limited to stocks/mutual funds and you will be able to invest into variety of alternative investments. 

Did I mention the previous owner drove his monster truck all over the front lawn?

That said, they do asset-based financing which seems like a good alternative.

Many investors from countries where currency is strong, are considering international real estate opportunities as a viable alternative.

Minus the $14.4k that I would spend on the alternate to rent, and I come to $82.6k additional cash needed during the two years.

You calculate an opportune time to sell for your alternative investment property.

Definitely great information to use here for starters, even seasoned vets looking at alternative ways for financing.  

I've looked into alternative nitrogen reducing systems (such as Bio-Microbics MicroFAST) which look promising, but I can't count on them. 

If they don't like the look of the deal they will tell you and likely ask for larger down payment   If the bank isn't willing to lend the money and you have good credit then you might want to reconsider the deal.....I am not a believer of hard money loans as an alternative personally so if banks says no I'll walk away

@William WatsonDiversification is the key when investing retirement funds; therefore, consider investing your Roth IRA funds in not only mutual funds but also alternative investments like real estate, notes, metals, etc.