How can I find out where a person is paroled to? Like whether they are paroled at a house or faciilty as a halfway house

You can ask the person.

If they are in a state halfway house or a center, it may be listed on their Department of Corrections web site. Many states ( not all of course) have the ability to search for imates in the system. This may include halfway houses that are state operated.

If this is not possible or they are in a private state funded center. There is basically no way to find their location without a court order.