Here are some sources on Robert Lang Campbell (1825-1874), the man who befriended and baptized John Morgan. He was from Renfrew, Scotland.
Here is his pioneer diary. Make sure you have some time and be ready to read a very touching story of the pioneer journey, 1846 in particular. (You can scroll down to the bottom of the page index and download a typed version of the diary.)
A BYU Studies Article on Campbell (downloadable)
Robert Lang Campbell Papers at the University of Utah
Robert Lang Campbell Collection at BYU
The item at BYU is a Great Salt Lake City tax record book.
The information on Campbell is thanks to a conversation on my favorite Mormon history blog, and a kind fellow reader and commenter from Scotland who serendipitously mentioned Robert Campbell in a conversation about something else.
Photo of Barshaw Park in Renfrewshire, Scotland, from http://www.flickr.com/photos/mike_cantwell/2421989892/.