We went to Nara from Kyoto, only about half hour by Shinkasen and spent most of the day but could have been there several more hours in order to see everything. Bringing a lunch would have been a great idea because when you are in the park your choices for eating aver very limited.
The park itself is beautiful and you can find so many temples and shrines any were you look. The entrance is free but there are fees for specific attractions such as Kasuga Taisha and the main golden Buda temple. There are tame deer all over the park and a lot of great photo ops.
Arriving in the city you will be terribly disappointed but the park and attractions are about a 15-20 minute walk. On the way back we took the public bus to the train station and by then you were happy to be driven, there is a lot of walking in ancient Nara.