I don't understand which of these you are asking:
1) what is the case under current law? or
2) what should be the case in a free society?
In terms of #2, it is up to H' to sign an agreement with H that maintains his access even after H sells his property to wal-store. It makes no sense to me to say that the person who owns the property H' has a right to access it. What if I bought land in Iraq and I need to use other peoples' property to get to it (ie, plane, car, camel)? Do the owners of the plane, car, and camel HAVE TO allow me to use their property? No.