Real Salt from Salt Lake City

A postcard from grandpa, from Salt Lake City, Utah.  What was he doing there? And, if he died in January, 1955, how come it's postmarked February 4? 
I think he only put 5 cents postage on it but the little bag of salt added weight.  The post office must have sent a notice to the address for more postage, and once it was paid, they added a stamp and another two postmarks, and finally sent it.  Sheesh.
The messy look of his writing makes me think he wasn't feeling well even then.  He must have borrowed a purple pencil, too, because his letters were always written with his prized gold fountain pen.
As to the question of what he was doing in Utah, he was simply taking the most direct route to California.

(Credit to the Sacramento Historical Society for the map)