HOWEVER based on your comments, I believe tenant's concern is actually the ducts as well as the vent grilles.

Country Escape with Outdoor Firepit & Grill. 

What about finding some land and parking it (and others) near a fire pit, grill etc that you may need to build/install for "glamping" in a communal but secluded setting?

If one has a goal of retiring early, I don't see any harm in putting in 401k funds, and using it almost like the Ronco grill (set it and forget it!). 

Fire pit, grill, outdoor shower, yard games, air conditioning on both floors, outdoor patio, smart TVs, washer/dryer, and a special house drink!

But I throw in wifi, smart tv, grills and an atmosphere like Hugh Hefner's mansion.The other 1% of my renters usually ask me "why are there naked women all over the place?"

House purchase price is 240k, 3 bedroom, 2.5 bath, 1520 square feet with a very large deck for outdoor dining, lounging, fire pit, and grilling.  

So for a person with little to no track record, expect to get grilled and a lot of no's, or getting focused direction as to the "skin" you have to bring into it and so on, they will not be quick to tell you how "easy" it can be because it won't be. 

Would love to chat more with you at our next event on 11/29 at Woodstone Pizza Bar & Grill in Rochelle Park. 

I recently found that key amenities like a spa, heated pool and outdoor gas grill were not listed in VRBO/HomeAway and Airbnb sites.