If you're into CCP history then Yan'an is the place for you, It was here that the Long March ended and where the CCP got ready to take over China. Although the city itself is somewhat drab it is worth coming here for the historic sights. There are a bunch of three and four star hotels as well as many cheaper ones, and restaurant choices are many. I especially liked the night market near the river for great barbequed food. There are flights from Xi'an to Yan'an but you can also take a (slow) train or get here by bus in about six hours.