April weather is hard. Transition form cold front with rain, nice day or two, repeat, to more summer patterns. Possible summer storm/showers then. You would just have to watch and check as it gets near. Could be great, could have fronts or all day rains.
Later in summer is less storms, but it DO get hot. Fall is often great weather with a lot of cooler nice days.

 

Thanks for all the great replies. I've decided one night at Lake of the Ozarks, 2 in Eureka Springs, and 1 in Hot springs, then over to Oklahoma and then northbound.

 

http://www.talimenascenicdrive.com

a possible on the way to OK

 

most definitely!
breakfast at the lodge on top, lunch in Talahina at Pams Hatefull Hussy Diner!