At the bottom are a couple of general links with information about Telegraph operations during the War in General. They will give you some leads to the answers to some of your questions.

As for telegraphs in Arkansas, it would seem that the two main Charactors were a Mr. Snow and a Mr. Ketchum (I have forgotten their given names at the moment) who seemed to be the most responcible for building the Telegraph systems in Arkansas Prior to the war. We know from records that they were responcible for the Pine Bluff Telegraph Company which had offices in Pine Bluff, Little Rock, Princeton, Arkadelphia and Camden at least by 1860, There were also telegraph lines which connected Napolean to Little Rock as well as from Helena. The Napolean to Little Rock Line probably ran throught the Pine Bluff Telegraph Company. We know that in 1862 Snow and Ketchum had a line as far down the Arkansas River as Red Fork. The Helena Line may have also ran throught the Pine Bluff Company but most likely ran to DeVall's Bluff.

Mr. Snow and Ketchum also were at least partners in the Arkansas Telegraph Company which ran north along the Arkansas River to Van Buren. They also constructed a line along the Railroad between Little Rock and DeVall's Bluff. According to several on this board David O. Dodd learned his Telegraph skills at Pine Bluff and Little Rock under to employ of Mr. Snow and Ketchum.

One of the limiting factors in determining where the telegraph line ran was the lenght of the lines necessary to run the shortest distance possible between to point, yet to be able to maintain the lines. This was because of the need to manufacture electricity by means of large chemical batteries. A single chemical battery cell was about the size of a pint jar, or paint can, but each cell could only generated 1 to 1.1 volts of electricity. It required 6 volts of electricity to power 5 miles of telegraph wire. Hence the "Telegraph Road" was most often not the best road between two points, but was the most direct route possible. Shorts and grounds were a constent problem that the telegraph operators had to contend with. The battery life was not very long and the chemicals in the batteries needed to be replentished on a daily basis. We have all heard of and seen the picture the "Battery Wagons" necessary to use a mobile telegraph in the field. This is why. That is also why there were no known mobile telegraph operations in Arkansas and all telegraph operations were from fit established sites.

Mr. Bill Shea has an excellant discription of the use of the Telegraph from Missouri into Arkansas by the Union army in Northwest Arkansas in his book on the Battle of Praire Grove.

http://books.google.com/books?id=e__U1AJ3WxwC&printsec=frontcover&dq=intitle:telegraph+inauthor:plum&lr=&as_brr=0#v=onepage&q&f=false
http://www.unitedstatesmilitarytelegraph.org/