You can take T 122/T 123 (Changchun-Guangzhou) to leave Tangshan at 06:34 and arrive in Chenzhou at 05:40.
Your boyfriend takes the bus1182/183 (Lanzhou-Shenzhen West), leaving Baoji at 06:22 and arriving in Chenzhou at 07:47.
The arrival time difference is 2 hours.
This is the most economical route.