A quick look at GOOG Maps, and without studying the 7+ day lie from a weather source, this route looks OK to me, with the exception of dipping further south in NM and AZ to dodge the elevations there. One could also go south/southwest out of OK City, toward souther NM, and then skirt low across NM and then lower in AZ, but there are many variations on a CC trip like yours:
Allentown, PA to Los Angeles, CA - Google Maps
I assume you are not sightseeing, just hauling azz, and if you have a lap top or smart phone with you, weather maps are easy to check on the go, or at night in a motel. We did a 2 month cross country trip this past summer, and both lap top and smart phone were handy to check the next day(s) 'guess', or the current conditions as we were motoring down the 2 lane blacktops.
My 50Cts...
GL, mD