best way to get to Foshan from Ke Yuan, ie Garden near Humen, Donguan?

For Ke Yuan, do you refer to the one on Keyuan Road?
If so, it is in Wanjiang District. From the garden, you can take a taxi to reach Dongguan General Bus Station on Wanjiang Road, where you can find frequent buses for FS General Bus Station.

It is suggested to stay near the Zumiao area. From Ling Nan Tian Di, Zumiao in FS, there are direct buses for the Xiqiao mountain, operating from 06:30 to 20:30 with interval around 15 to 30 mintues. The close, clean hotel near Zumiao is the Home Inn on Zumiao Road.