If you're combat roll is solid, I've got a Browns Canyon run Saturday around noon-ish. That's a quintessential Class III on the Arkansas. Nothing in there is very difficult or consequential if you swim. Only me and a friend confirmed right now (two others are "maybe's". I'm driving from the Denver area if you want to shuttle.
There's another group doing it a little earlier in the day.
You can find the link to that thread here
If you want to warm up a bit before you jump into a Class III, that Filter Plant run is a good bet.