Under the newest tax laws that just came into play in December, an individual can gift or die with a combined $11.18M before being subject to transfer taxes (and $22M per couple with portability or split gifts). 

Do you know of any short-term or system that is portable if new owner does not want to assume a contract.  

I have a portable wood stand I set it on that stays on the job site.

Based on feedback from other hosts I will probably add a TV in the living room and portable air conditioning in the bedroom this Spring.I am very careful not to allow long stays because I want families that are vacationing -- not homeless people who seek to establish residency. 

Works great... easy to install and portable.  

This will require some html and css skills at a minimum but unlike the previously mentioned hosted domains your code will be portable if you upgrade later.If you plan on designing something professional with some modicum of support you will end up paying something.

Heat pump units are more efficient than window or portable air conditioners, more aesthetically pleasing.

Especially since I would have to get one for each room.I'm also considering one of those portable air conditioners, but they still need to vent outside. 

The installation of one or more portable space heaters shall not be used to achieve compliance with this section.Emergency Egress requirements- R310.1 Emergency escape and rescue required.Basements, habitable attics and every sleeping room shall have at least one operable emergency escape and rescue opening.

My new  tenants upstairs apparently brought in a "portable washer" which has leaked into the downstairs unit - destroying the tenant's bed and TBD on the rest of the damage.