please help arrange my tour to Xian

Hi. if 7-8 days in Xian, suggest you live in the city center:
I recommend Bell Tower Hotel, whose entrace is just face the Bell Tower. Melody Hotel is few hundred meters west of Bell Tower Hotel. It has airport shuttle bus stopping there.

Tongchuan is not suggested to go. For Weinan, you can get to climb Mt. Huashan in Huaxian County. This will cost you 1.5-2 days. Scenic spot Worthwhile to visit in Shangluo is the Jinsi Valley and carst caves. Hanzhong has the old plank way on cliff. The city is better than Shangluo, I think. You can spend one day for each place. There is a lot of places to go inside the city. In addition to the Bell tower, Drum Tower, you can get Muslim Street, Great Mosque near the towers, Big Wild Goose Pagoda, the City Wall, Terra Cotta in suburbs and so on.