I have never had that problem and do not often stop at KOA
But I have two power cords for this RIG
One has a 50 amp park end plug and a 50 amp Marinco-outlet for the RV end
The other has a 30 amp park plug and a 50 amp Marinco
You can get two things at Camping world and several other RV dealrs
one is a short 30 amp cord (like 1') Has a 50 amp Marinco outlet to mate with the RV
The other is a 30 amp extension cord.
My cord is 10 years old..In that time the mating plug & Outlet went bad.
So i cut them off and joined the short "Adapter" to the longer "Extension" using good solid electrical practice (I will not describe)
Result.. I have two power cords..no adapters needed.