Hot Rod Power Tour/ Pump Gas Drags/ Drag Week - somewhere to buy tires along the route?

my tires kinda disappeared on me over the last two days, not sure what happened, i haven't hardly even been driving it. fronts are good, but i need some new rear tires (imagine that...). No place in town has any in my size, 315-30-18. Does anyone know if there is anywhere between southwest missouri and cocoa beach, FL that would have some in stock? i don't know if my BFG drag radials wil make the long haul...but i'm gonna try

any help at all would be appreciated

thanks,
Ben