It's just a bit east of Fort Smith. I take I-40 east into Arkansas, then take I-540 south to the Hwy 59 exit (I think that is the 2nd exit off of I-540. Then 59 south, and in about 5 miles you go on a bridge over the Ark. River. Just past the bridge, the park entrance is on the left.
I'm planning on bringing my kayak this year. Might as well make use of the water.
I know how you feel... usually the emptier the campground, the happier I am. But this is pretty fun, with a bunch of good and friendly folks. Last year I didn't arrive until Saturday, right as they were serving up the ice cream social, and even so they gave me firsts and seconds.