I was wondering if Alyson Hannigan would be guest-starring, but apparently not. However, there are some interesting names on the cast list:
Felicia Day (Vi in Buffy, Penny in Dr. Horrible)
Nico Cortez (Young Adama in BSG Razor) as Jo's father, probably in flashback since he looks a bit young.
Aaron Douglas (Tyrol in BSG)
Nico McEown (Cody in American Pie Presents: The Book of Love)
Will Wheaton (who?) as Dr Isaac Parrish, has been in a previous episode.
Nicholas Elia (Ben Braeden in Supernatural) as Young Parrish
Looks like it might be interesting and I suspect that people who like "kidfic" about normally adult characters (I don't much) will love it.