I would want to get a futon bed for hosting larger groups, but beyond that, I already have extra linen and such that I would need to get started.

You also need to look at what types of linens you are providing.  

This could help you decide if it’s worth doing.Broadly Speaking you’ll need to have at least 50% occupancy to make most Airbnb’s worthwhile.Remember you’ll be paying all utilities, cleaning Supplies and fees, supplies such as paper towels and TP etc. which can add up to several hundred a month.Lastly furnishing the home including nice linens and towels (3 sets per bed and 3 sets of bath towels per bathroom) for this alone I’ve spent between 5-15k If you or your family would want to ever stay in the home that’s an incentive to Airbnb, as you can use it yourself when not rented.Some of ours we rent month to month in the winter and short term in the summers.cheers,Jessica 

But I think what my neighbor did, combining the two units, is a clever way, if you decide to go through with it.

My wife will be there and have the washer & dryer running with linens or towels, and she'll be running the vacuum cleaner when we show up. 

Get a clever URL.

Who buys the linens you or me?

When someone with reasonable credit calls me for a 2nd opinion after calling BR, usually the rate ends up being very similar (a pinch lower today, a bit higher tomorrow, whatever), but all the thousands and thousands of dollars in (cleverly renamed) marketing fees go away (THIS is where the action is), holding all else constant. 

This is because I don't totally trust the bank to make the "tenant" account deposit-only; a clever tenant might try to use my name, the account number they know, and the bank's routing number to pay a bill or something.

@Anthony HolmanThat is super clever on your partMost developers want fee simple transaction but if your location is that prime then you probably can get away with it