You would need an invasive species sticker. A lot of people get them online then put the online receipt in a zip lock. That way if you have to boats that you will paddle you only buy one sticker. This won't work for two boats being paddled at the same time. Either way I don't know the minimum flow, but I loved the park. Someone told me that Eric Jackson said it was shit. I have not heard that review, but I liked it a lot, and I am convinced that the second wave on river left is made of pure glass
If you are a decent playboater you will have fun, and so will your beginner friend they have a local kayaking school that teaches kids to boat up there. Also it is not a 6 to 7 hour drive from ogden more like 4 to 5.