I would say from my recollection there are a number of class 3's, just spaced farther apart than pumphouse. Rodeo rapid/hole can flip a raft pretty easily.... well.... at least it could after a couple of beers 15 years ago....
hrmmmm... I see Burns Rodeo Hole in Banks and Eckardt's book rated as "advanced playboat" ... not sure what that means. Seems odd that's there's so little info on this 30 miles of Colorado River, I guess that's why I'm asking.
Rodeo is the only thing to worry about and it can flip a raft if your not careful. Just skirt it, it's not that bad. The remainder of the trip is mostly flat. Great fishing, lot's of private land, not very many public campsites.
There are other rapids between S.B. and Dotsero. Below S.B. there are several rapids w/ wave trains. Windy Point Rapid being the largest II+ (really nice camp) Alkali Drop is a mile or so below Catamount (good camp), don't be surprised when you see a horizon line. Landslide aka Burn's Rodeo Hole has some powerful waves and many rocks III+. I have seen a drift boat pinned on the bridge @ Pinball Rapid II+. Twin Bridges & Horse Creek can grow larger w/ high water. Other nice camps include Jacks Flat in the Bull Gulch WSA, or Lyonns Gulch.