Your heir will need to accomplish a timely form five transfer.
Here is the form.
http://www.titleii.com/pdf/010205-Form5.pdf
I think the check box for the heir is number three on the left of the form.
There is no transfer tax for the heir, but other things apply. The heir cannot be
a felon conviction etc... and must live in a state that allows this.
You should inform the potential heir of this responsibility, since the
hypothetical case assumes you are no longer around.