Yep, I'm in Golden. I'd go with you later in the season when prime time is over... I'm trying to get my days in on some harder stuff right now.
For now, I know you will find a ton of beginners and intermediate beginners if you post on the Trip Planner forum here: Trip Planner - Mountain Buzz
Also, I think the Colorado Whitewater Association is a good resource for new paddlers.
Right now, in Colorado in June, it is going to be hard to find an advanced paddler to go with... they are all skipping their best friend's weddings so they can paddle harder stuff... but I bet you can find some other people who are starting out. But be careful because everything is cranking right now.
In order to prepare for paddling in a natural river channel with other boaters go ahead and get a river knife, a whistle, a throw bag, and some decent river footwear. A throw bag takes some small amount of expertise to use and to safely stow in your boat (so it doesn't come out when you swim and cause a hazard), but I'd get one now and ask a more experienced partner how to throw it and how to stow it (get a caribiner for that, preferrably one with a 'quick lock'... I don't like non-locking caribiners on the river unless they are in a pocket). Don't carry a rope without a knife attached to your PFD.