After the 1855 Assembly session ended (Goss was succeeded in the next session by Democrat James Weaver of Lisbon), he moved to Freeport, Illinois to join his brother N. S. Goss in operating a large grocery store for about one year; he then moved to Waverly, Iowa, and went into the real estate business for about two years, after which he moved on to Neosho Falls, Kansas, where he (along with his brother N. S. Goss and two others) formed a company, purchased several hundred acres of land, platted Neosho Falls, built a dam, erected mills, and made other improvements. He continued doing business at Neosho Falls until October, 1861, when (the American Civil War being under way) he organized a company of cavalry of which he was elected captain; the company became Company F of the 9th Regiment Kansas Volunteer Cavalry. Company F was in the battles of Cane Hill and Prairie Grove and many smaller engagements. For a large part of their service time they were stationed on the frontier, serving as scouts. They were mustered out of the service in January, 1865, "Goss having served as its captain, participating in every march, movement, etc., his command was in". Shortly after his return from the army, he sold his interests in Neosho Falls.