My daughter stayed there two years ago, when she was 5, and loved it. They had computers, plus planned activities, etc. I believe they offer meals as well. I can't remember exactly how much it was, but I believe you get a discount if you have multiple children go. And yes, you can make reservations.
We are going this year, and she will be almost 9. I asked her if she wanted to go to Camp Little Rock again, and she is undecided (she thinks she is too old, although I think they take children up to age 12). So, your children are definitely not too young, and will probably love it at their ages!