JR Dream overnight bus? Advice?

We are thinking of catching the JR Dream overnight bus from Tokyo to Nara but cant find much info on the net about it (other than japanese sites). Is it correct that we can use our JR Rail pass to board the bus? Do we need to book? And is worth it???!!
We thought we could save on one nights accommodation if we could use our JR Rail Pass

I could only get this (way blow)in English. I tried the bus site but most of it is in Japanese. Note that they arrive in Kyoto at 6 am, when few places are open, except, most likely, the JR Kyoto station. But not too many food places will be open..as for Nara, this is a small town-by Japanese standards-and practically everything would be closed at that time. You can't start sightseeing for 2-3 hrs at the earliest.In addition another site noted that it is hard to sleep on the bus, if only because it stops often (with P.A. announcements, people noises etc).
I had rather get a cheap room at a hostel the night before and after and use the JR pass to travel quickly from Tokyo to Kyoto or Osaka, both places with hostels (Nara has few cheap hostels.one is 2 km from downtown) Nara is better seen as a day trip from Kyoto or Osaka.
JR Night Bus.
Dream Kyoto, operated by JR, is an overnight bus that departs at 10pm from the stop at the Yaesu South exit of Tokyo Station. You can buy tickets at the Bus Ticket Center located there at the exit. It arrives in Kyoto at 6 in the morning.For those interested, a women-only bus called the Lady's Dream Kyoto leaves and arrives an hour later than Dream Kyoto.

The Japan Rail Pass covers the highway buses between Tokyo and Kyoto and Tokyo and Osaka, but I don't think it covers the one to Nara.

That's right the JR pass covers the trip to Kyoto but from there you will need to transfer to a train and pay the rest of the way.