I replaced both of my running boards with nerf-bars on my 04. Took about two hours start to finish. The biggest pain is not the big bolts holding it to the truck, it's the small bolts holding the plastic and metal frame together. They all bolt to the undercarriage to keep it nice and clean looking. There's lots of them too. The two big bolts holding it in were about 7" long and they're a weird size head. I think 17 or 18mm. Whatever does not come with a standard/metric tool set. I lucked out and had a socket set that was separate from my tool kit.
I agree it may take some time, but if you can get a wrench in there it's not hard to do at all.
BH