I've ridden that area a lot on Flood Run day. Sometimes on purpose so I can dip down into Maiden Rock and/or Nelson to check out the bling and brat. Generally there is little traffic up in the interior hills on the secondary roads. Probably the biggest headache is getting over there as you inevitably have to cross over somewhere and you don't want to do that in the busy period. Plan on crossing no later than 9 am.
......... just look over your should for the airplane.