In a previous question I asked about how to best gain components for Rituals in a world where magic is not as common.
In our last session we completely conquered a fort and decided to lay claim to it as our Base of Operations. However our quest needs us to leave for parts unknown shortly. As a new ritual caster (level 6) I would like to set up some rituals to help us in our travels and to let us return.
I have a general idea of what rituals I want to use to protect the fort, and others for ease of storage (should we find treasure hoards). But the one thing I am unclear on is how to set up an easy way to return once finished our quest.
I know I can master the Linked Portal Ritual at level 8 (if I can acquire it) but I don't believe our fort has a permanent magic circle. What steps could I take to prepare one (provided our DM allows it)?