Scout at Sunshine river right, its the fourth bigish rapid, with concrete and a photographer river left at the bottom. Sledgehammer, Wall slammer and Boat Eater are also somewhat challenging. Sledge is after Sunshine. Wall slammer comes at the end of the Narrows where the incline passenger train and it's viewing deck are. Boat Eater is lower down and I don't remember the landmarks. I think the usual line is left at lower flows, but I could be wrong, and I have never scouted it or anything other than sunshine. There is a Arkansas river map at: Arkansas Headwaters Private Boaters - Colorado State Parks
There is a lot of debate about the right rating for the Royal Gorge varying from Class III to IV+ or even V- at high water. At the current level most people will call it III+ or IV-. You will probably be fine, but only you can make the go/no go call.