Could we have a portable portal device that we can carry on hand?
so we can set it to a portal (right click on the target portal Stabilizer) destination. So we can then use it to teleport back.

Could also have an advanced version of it, that allows up to 5 destinations, and you can change destination with mouse wheel for instance or using the existing portal gui.

Craft recipt would be a Stabilizer + Target Device + Basic Energy Cell
and a similar for upgrading to advanced version.