This:
The House of Zebulon is a small stone cube, painted with a door and windows. When the owner desires, he may cause a doorway to appear. Stepping through this doorway carries the person and anyone or anything with him inside the cube to a small apartment of six rooms. Here the person may stay as long as he wants. He may leave the house at any time by stepping through the same door. Once a week, he may project the doorway to any location he is familiar with as in the spell Teleport"