Reading the posts, it appears that the only way to get guest star (or original airdate, director, etc.) information is to first choose to record the show, the select "Season pass and other options", then press the "Info" button.
I don't think this information is even available for a show that's already ended.
It would be nice if there were a quicker way to see this information.
Actually you should be able to get that information while viewing any episode description for a show.
If you're trying to get here from the LiveTV guide, yeah, you may need to jump through those hoops to get into the episode details screen. It isn't clear if that's what you mean. (I never use LiveTV or the guide therein.)