"Jehovah's Witnesses--Proclaimers of God's Kingdom" page 489: mentions "From Chefoo, thousands of letters, tracts, and books were sent out between 1891 and 1900" "C.T. Russell spoke in Shanghai and visited 15 cities and villages, 1912" "Colporteurs distributed much literature up and down the China coast, with trips to the interior, 1912-1918"
The lecturers spoken of above are probably those individuals known as "pilgrims" or travelling overseers. I have seen several instances here in Florida newspapers where these Bible Students speakers visited, and the location and time of their lectures. Pastor Russell himself visited in Florida on several occasions and gave his lectures as well.
From the Bible Students I found the following info, which I suppose came from Zion's Watch Tower, but I don't see any dates.