Which city of Fujian will you go ?
There is bullet train from Shanghai Hongqiao Railway station to Xiamen Fujian.
The accommondation condition is different in different cities in Fujian. Which city will you stay in?
Other than Hakka housing, you can also go to visit the famous Mount Wuyi(https://www.travelchinaguide.com/attraction/fujian/wu-yi-shan.htm) which is in Fuzhou. Its beautiful mountains, vigorous rocks and limpid waters are legendary.