I'm inclined to go against the fluff-as-written, and go with a short ranged teleport, that is powered by the same interactions that cause the shadowfell and felwild in the first place.
This allows me to place a variety of restrictions on the ability, as long as they are consistent with teleporting in general.
This allows me to place a variety of restrictions on the ability, as long as they are consistent with teleporting in general.