I may be a little biased, but I really have to suggest the Johnson Shut-ins area. It's closed until Memorial day, but it's a fantastic place to camp. You have Elephant Rock park, Fort Davidson Battlefield, Taum Sauk Mountain all nearby, along with several other great places to visit. Lake Wappapello State park has nice facilities, Sam A. Baker State park is a nice place. Big Spring park in Van Buren within the Ozark National Scenic Riverways is a beautiful place to camp, canoe, etc.
I have to say the area around Johnson shut-ins is my favorite area. Beautiful scenery, several quaint small towns with great food, shops, and bed & breakfasts.
The Van Buren area would be my 2nd favorite area. Again beautiful scenery, Nice small town atmosphere, good restaraunts, some with nightly entertainment.
I had a little trouble finding information about some of these places on the net, but ask anyone that has been to these places, and I'm sure they'll confirm what I say.
Good luck and have a blast.