I agree with Dave (except about Butress rapid approaching V-)
There is no real move to make in this rapid, everything very straightforward. I would say class III+ in difficulty, class IV+ in consequence; if you go upside down for more than a few seconds, plan on some extreme cranial impacts.
About a put-in...you can put in above butress rapid, huge pull out on both sides. Or if there is at least 150-200cfs, you can put-in about a mile up where four mile creek enters boulder creek.
Like Dave said, the more water the better. This section above the play park becomes very pin prone below 150.
I'm usually down for a Saturday morning run or weekday evening run.
Dave, let me know if you ever want to run this after work, that is of course if we ever get some water.