I live in Nara so I'll give you a little info about the area. For general sightseeing I think one full day is enough to see all the main sights in central Nara. If you get off at Kintestu Nara it's a 5 minute walk to get to the main temples and you can see pretty much everything on foot.

I'm not sure of the exact location you will be staying at but Nara doesn't have as much variety as Kyoto so I wouldn't spend too long here. It's a tourist town and the shopping isn't very good. That said, it's a beautiful place.

I'd suggest you visit Asuka if you have time. In March the weather should be very pleasent and it's a great day out. You can see the very early burial mounds that were erected before the capital moved to Nara. You can rent bikes and visit all the sights in one day.
http://www.flickr.com/photos/listless/sets/

Check out my Flickr page set list if you want an idea of how some of the kansai area looks.

Other than that your list looks great. I went to Tokyo last year and Nikko. It was great fun and if I ever get the time (and money) I'll definitely go again.