This might be a good idea, if the interest rate spreads are in your favor.

not sure which is favorable for you situation but what I do know is:car loans will impact your debt to income ratio, but as long as you are in the preferable % range the lender wants to see you are good also installment debt utilization does impact your credit scores. 

@Eric Smith Just do it the old fashioned way, save up your money.

If you were to refinance, the terms will likely be less favorable than the terms of the initial purchase loan.  

Cut any holes in the unit, floors, doors, windows, appliances, or fixtures in the unit or change the appearance of the windows in any fashion.

@Isaiah WrightI haven't done a seller financed deal yet, but I've been doing obsessive research in the past couple weeks.This pros of this purchasing strategy are that the terms are negotiable, and you can get away with putting low or no money down in exchange for a favorable interest rate and sale price to the owner.

On top of these avenues for structuring deals, there are many levers you can pull to make deals more favorable and provide higher returns.

Given that you and your spouse have great credit, that would be a compensating factor in your favor. 

Maybe I am not doing hosts a favor by letting them know when we leave.

You would make more money putting $250,000 down on 4 properties then buying a single 1 million dollar property if financing terms are favorable.