Your bike sounds well prepared. Others than myself have long distance experience but first thing that comes to mind is take shady breaks occasionally for relief from unrelenting sun and mind and fanny numbing boredom of freeway travel. Once approaching Kings Canyon from Kern River side you will have a blast on the climb up into the park, it is just getting that far that has you concerned? Maybe try the rubber band cruise control on the trottle for a little wrist relief and mental stimulation when open roads permits such goofy distractions?
A spray tip for a water bottle might help mist you and bike down when heat feels oppressive. Stay hydrated , wear bright light colored well vented gear if possible and expect to be passed frequently.