The road to crystal is pretty chill. You shouldn't have a problem in a stock truck. It is rough and slow though. Plan on almost 45 min to an hour to get there from marble. I just put it in low and creep to minimize vehicle abuse (mostly loose rock crawling). Your biggest problem will be passing other vehicles due to heavy traffic. I would imagine that area would get packed with ATVs, motorcycles, jeeps and occasional hard core sedan drivers on Labor Day. Be prepared to pull over or back up every 5 min or so. Going to Led King basin would be a good alternative. The road is smoother and the views are better. You can check out the NF also. Maybe mountain bike down it. My opinion, crystal mill falls is kind of whatever. The road gets real rough at, and after, the NF section (between the NF run and town of Crystal). A stock truck can due the loop (I did it with a fully loaded Tundra extra cab), but it might get a little sketchy with the spud in the back and all. There are a couple of places that made me very uncomfortable.
Enjoy, its one of the coolest places in CO.