The "Round the Island" bike race is 113 miles and skips Ka'ena Point and the Leeward side of the island. So the race route is do-able in a day. If you want to do the whole circumference of the island you are looking at 140+ miles and a fairly difficult sandy/off road section around Ka'ena Point.
Rob still hanging around in the Eugene OR area?
He leads tours in Hawaii and South America, among other places.
Have known him for decades. Used to ride cross country on tandems, as stoker, with Penseyres.
I heard Rob moved to Tustin of all places. Saw him on a ride last year.
Pete Penseyres has a ride every Wednesday which I go on sometimes.
Even at 65 the guy beats us all up the hills which there plenty and steep.