Found a couple of things for you. Reference: Lothrop, Charles H. A History of the First Regiment Iowa Cavalry Veteran Volunteers. Lyons, Iowa. 1890. Pages 61-73. March 14th Headquarters established at Clinton, Missouri, headquarters removed to Butler, Bates County on April 8. "Posts were also established at Clinton, Henry County and Osceola, St. Clair County." Colonel Moss and afterward Captain W. E. Leffingwell, Company B commanded at Osceola. In April, men from Osceola fought at Montevallo, Vernon County and at several other locations. By September, they had marched to Springfield.

Reference: Gibson, Charles and Gibson, E. Kay. The Army's Navy Series, Dictionary of Transports & Combatant Vessels. Ensign Press. Camden, Maine. 1995. Page 294. The Silver Lake. Chartered July 19 to August 18, 1862. Note states vessel was burned by rebels in Lime Creek, Osage River, September 3, 1862. Apparenly repaired since it was chartered later. One source lists it as 450 tons and another as 70 tons. Considering where it was located, 70 seems more reasonable.

Hope this helps!