GwenInLA1,
Sorry to chime in a little late here but there a few interesting historical sites in Eastern AR. that I know about.
On Hwy. 64 East of Wynne is a small town called Parkin. There is a historical Indian site there, complete with a tour guide I am told. They have just built a new facility right on the St. Francis River, you can't miss it. One word of caution though, lock your doors, and be gone before Sundown, Parkin is not a very hospitable town after dark, especially to outsiders.
On Hwy 49 around the town of Harrisburg there is an old plantation called the Parker Homestead. They have a tour there with people dressed in 1800's fashion working on the plantation. After it is over you can even buy some honey that they make there on site. I've never been but they tell me it is a great tour.
While you are in Harrisburg, I recommend stoping by the Food Giant, as they have one of the largest inventories of firearms in Eastern AR. If you want to go on up to Jonesboro which is 15 mi. north of Harrisburg, stop by Trent's Rental Center to check out the largest selection of Assualt Weapons in North East AR. Trent is located on Stadium Blvd. just beside the Stadium Place Apartments.