I hope this isn't redundant information.

(Source: "Record of Events for the First Indiana Cavalry" IN, Supplement to the Official Records" Part II, vol. 15; Serial No. 27 (1995) Janet B. Hewett principal editor. Wilmington, NC: Broadfoot Publishing Company.)

Note, these excerpts are from the "Regimental" R.o.E.s, company R.o.E.s have no detail. (asterisks indicate removal of non-pertinent material).

(p. 176)

Stationed at cross-roads, Izard County, Arkansas, May, 1862.
* * * *
May 26-28. – Started for Houston, Missouri and arrived at Pilot Hill at noon of May 28. The command was there divided, and Colonel Baker, with portions of Companies B, D and F and two steel guns, started for West Plains Missouri.

(p. 177)
May 31. – The balance of the regiment, under command of Sergeant-Major [SIC!] Josiah Forth left for Mount Olive, Arkansas and on May 31 encamped at cross-roads junction of the Jacksonport, Yellville and Mount Olive Roads.

Stationed at Augusta, Arkansas, June, 1862.
* * * *
June 1. – Five companies under command of Major J. Forth, were encamped at Cross-Roads, Izard County, Arkansas. A scouting party under charge of Captain [George P.] Deweese encountered the enemy at Eleven Points, Missouri. Private John Smith of Company D was wounded in the left arm.
June 11. – Marched for Pilot Hill, Arkansas.
June 12. – At noon of June 12 we entered the town, meeting there Colonel C. Baker with the other three companies, which had just returned from West Plains, Missouri.
June 22. – The regiment remained in camp at Pilot Hill until June 22, having scouting and foraging parties, scouring the country continually.
June 23-27. – The regiment, under command of Lieutenant-Colonel W. F. Wood. marched for Jacksonport. Arrived at Jacksonport June 27 . . .

I'm unsure what word in the original document "Sergeant" replaces (entry of May 31); I suspect it was "Second" (i.e. "Second Major Josiah Forth"). These events all relate to late May & early June, 1862. As far as I'm aware the First Indiana never returned to Oregon Co. Missouri after that time.

I hope this helps!

John