Flip flops are a must and quick dry clothing is recommended. Also, I seriously recommend not wearing white short. I made that mistake and it was an awkward rest of the day with the black boxers I was wearing.
To me KRR is too short and really not that great a ride for the risk of getting soaked. However we do ride it with cheapo Dollar Tree ponchos and we keep our feet up. Yes we do get wet but it isn't that bad.