Pumphouse down is easy, you will be fine. Blue below Green Mountain is a serious step up from the Upper C, but still relatively easy. At these flows (1400+) you will encounter a handfull of II-II+ play spots with good eddy service, followed by a solid III rapid and a couple of small dam drops that can trip up the unsuspecting beginner. If you are going to take Highway 50 over you should hit up the Ark, lots of good II/III stretches to choose from (JV to Ruby, Stone Bridge to Salida, Salida to Rincon, Cotopaxi to Parkdale) plus there is a stretch on the Gunnison you would probably like.
No matter where you boat, I hope you have fun