If anyone wanted to go see Gallifrey I could probably think of an excuse for Narvin to take someone. Alternatively, since Narvin's reason for being on Quadratus is to look for technology from other universes that might help Gallifrey, he could be pretty easily convinced to go visit someone else's universe.

And if anyone wants to thread out a Travel Agent interaction (taking people there, bringing back in an emergency, or anything else) I can volunteer Niles for it.