Downside is that they are usually not the cleanest of people, even if they're not party-throwers, so you should expect a little more cleaning up than normal. 

The interest and down I suggested is a fair representation of the lender's risk, in other words, if things go wrong and the little old lady who sold the property has her attorney involved about something else and then discovers her being screwed over, there are many paths they can take to clean a predator's clock. 

Do I include a cleaning fee with the rental agreement?  

You want to make your property safe, clean, appealing, and functional.

Oh well, less cleaning to do!

Their daughter owns her own cleaning company and all I've had to do is text her check ins and check out days and my cabin is cleaned.

For a higher end venue (the stuff in the $5000+ range) in my market the rental fee will also include cleaning, day-of planning/setup, and valet parking.Sunday brunch weddings are starting to become increasingly popular for this exact reason.

Close on the property, clean it up, and sell it at retail.Assuming the only major problem is the junk.

If you want to keep it clean and not worry about the underwriter hitting the non-borrowing spouse with the liability of the property taxes and homeowner's insurance (yup, on title means YOU are obligated to pay that, even if they are escrowed, etc), keep it totally separate. 

One thing to consider is how clean your list is.